Interference correction of clinical assays

Abstract

Improved methods of analyzing a biological sample to determine a target analyte concentration corrected for interference are provided. The methods provided herein include analyzing a biological sample with one or more assays and applying data to determine a corrected concentration of a target analyte. Also provided herein are clinical chemistry instruments that include one or more assay systems, a processor configured to receive data from the one or more assay systems and determine a final concentration of a target analyte corrected for interference.

Description

Background Technology

[0001] Determination of the concentration of specific target molecules is an important tool in many fields of research and medicine. For example, clinical chemistry assays used to determine the concentration of target molecules (e.g., electrolytes) can be crucial for making accurate diagnoses and / or determining appropriate treatment plans for patients.

[0002] Interference is a common problem in various assays, including clinical chemistry assays. More specifically, in assays used to determine the concentration of a particular target analyte, interference can cause falsely high or low reported target analyte concentrations, depending on the nature of the interference. In a clinical chemistry setting, such erroneous results can lead to adverse patient outcomes by causing incorrect diagnoses or inappropriate treatment plans. At the very least, it may force patients to undergo unnecessary additional testing (including, for example, additional unnecessary blood draws) to obtain an appropriate diagnosis or treatment plan.

[0003] Interference can originate from a variety of sources. One example of measurement interference is hemolytic interference. In electrolyte measurements (such as potassium measurements), hemolytic interference is a major problem when determining a patient's electrolyte levels to assess whether the patient has an electrolyte imbalance (e.g., hyperkalemia or hypokalemia). This is particularly problematic in the emergency room, where blood draws can be more difficult and hemolysis is more likely. Electrolyte imbalance can be a medical emergency, and hemolytic interference can lead to uncertain results in electrolyte measurements, making it unclear whether elevated or normal results are accurate.

[0004] Therefore, an improved measurement method capable of correcting for interference is needed. Summary of the Invention

[0005] In at least one aspect, this disclosure provides a method for analyzing a blood sample to determine a potassium concentration corrected for interference, the method comprising at least the steps of: analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a corrected potassium concentration corrected for interference.

[0006] On the other hand, this disclosure provides a method for analyzing a blood sample to determine a potassium concentration corrected for interference, the method comprising at least the following steps: analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interference indicator in the blood sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference.

[0007] On the other hand, this disclosure provides a method for determining potassium imbalance, the method comprising at least the following steps: analyzing a blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines the concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a corrected potassium concentration corrected for interference.

[0008] In another aspect, this disclosure provides a method for determining potassium imbalance, the method comprising at least the following steps: analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine the concentration of an interfering indicator in the blood sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for the interference.

[0009] On the other hand, this disclosure provides a method for analyzing a blood sample including an interference indicator to determine a potassium concentration corrected for the interference, the method comprising at least the following steps: analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration in the blood sample that is not corrected for the interference; receiving data at a processor corresponding to the uncorrected potassium concentration; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of the interference indicator; and receiving data at the processor corresponding to the concentration of the interference indicator; and determining, by the processor, a corrected potassium concentration corrected for the interference, wherein the corrected potassium concentration is determined by applying data from the second assay to data from the first assay.

[0010] On the other hand, this disclosure provides a method for analyzing a blood sample including an interference indicator to determine a potassium concentration corrected for the interference, the method comprising at least the following steps: analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; receiving data corresponding to the initial potassium concentration at a processor; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of the interference indicator in the blood sample; and receiving data corresponding to the concentration of the interference indicator at the processor; and determining a final potassium concentration corrected for the interference by the processor, wherein the final potassium concentration is determined by applying data from the second assay to data from the first assay.

[0011] In another aspect, this disclosure provides a method for improving the determination of potassium concentration in a biological sample, the method comprising at least the steps of: analyzing the biological sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the biological sample with a second assay, wherein the second assay determines the concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a potassium concentration, wherein the corrected potassium concentration is corrected for interference.

[0012] In another aspect, this disclosure provides a method for improving the determination of potassium concentration in a biological sample, the method comprising at least the following steps: analyzing the biological sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the biological sample; analyzing the biological sample with a second assay, wherein the second assay is performed to determine the concentration of an interfering indicator in the biological sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference.

[0013] On the other hand, this disclosure provides a method for indicating whether a patient has an electrolyte imbalance, the method comprising at least the following steps: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected electrolyte concentration.

[0014] On the other hand, this disclosure provides a method for indicating whether a patient has an electrolyte imbalance, the method comprising at least the following steps: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial electrolyte concentration in the biological sample; analyzing the biological sample with a second assay, wherein the second assay is performed to determine the concentration of an interfering indicator in the biological sample; applying data from the second assay to data from the first assay to determine a final electrolyte concentration corrected for the interference; and reporting the final electrolyte concentration.

[0015] Those skilled in the art will understand that, in some embodiments related to the foregoing, the first determination is an ion-selective electrode (ISE) determination.

[0016] Those skilled in the art will understand that, in some embodiments relating to the foregoing, the interference indicator is hemoglobin. Additionally, in some embodiments relating to the foregoing, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. Furthermore, in some embodiments of the art currently described, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some additional embodiments, the quantification further comprises determining the multicolor optical density (OD) of the biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variants include lipemia and bilirubin. In some additional embodiments, generating the covariance matrix comprises adding irrelevant variants (referred to as "regularization" by those skilled in the art) to the covariance matrix. Furthermore, in some additional embodiments, the non-hemoglobin variants include instrument-induced variants.

[0017] In some embodiments relating to the foregoing, the method further includes the step of using the ISE assay to quantitatively determine the uncorrected potassium concentration.

[0018] In some embodiments relating to the foregoing, the step of applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the step of applying the data further includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subsequently subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0019] In some other embodiments related to the foregoing, the method further includes the step of indicating whether the corrected electrolyte concentration is above or below an electrolyte imbalance threshold after reporting the corrected electrolyte concentration.

[0020] In some embodiments relating to the foregoing, the report further includes reporting the uncorrected electrolyte concentration.

[0021] In some embodiments relating to the foregoing, the report includes a comparison between the reported uncorrected electrolyte concentration and the corrected electrolyte concentration.

[0022] In some embodiments relating to the foregoing, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration if the difference between the corrected electrolyte concentrations is greater than the reporting threshold.

[0023] On the other hand, the disclosure of the currently described technology provides at least one method for determining potassium concentration in a blood sample, an improvement of which includes the step of determining a corrected potassium concentration by attenuating interference. In at least some embodiments of this aspect, the improvement further includes the step of applying the concentration of an interference indicator to an uncorrected potassium concentration that has not been corrected for interference to remove interference. In some other embodiments, the interference indicator is hemoglobin. In some embodiments, the improvement further includes using an ion-selective electrode (ISE) assay to determine the uncorrected potassium concentration. In some other embodiments, the improvement further includes the step of using a lipemia, jaundice, and hemolysis (LIH) assay to determine the hemoglobin concentration. Furthermore, in some embodiments, the method further includes the step of quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination includes measuring optical density at two or more wavelengths. In still other embodiments, the quantitative determination further includes the step of determining a linear combination of the optical density (OD) of the biological sample at two or more wavelengths. Furthermore, in some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of the biological sample, the multicolor OD minimizing the effects of non-hemoglobin variant sources, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variant sources in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variant sources include lipemia and bilirubin. In some other embodiments, generating the covariance matrix comprises adding irrelevant variants (referred to as "regularization" by those skilled in the art) to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variant sources include instrument-induced variants.

[0024] In some embodiments, the application step further includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the application step further includes the steps of: multiplying the concentration of the interference indicator by the correction factor to determine the interference magnitude; and subsequently subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0025] On the other hand, the disclosure of this technology provides at least one method for correcting interference in a measurement, the method comprising the steps of: analyzing a sample with a first measurement, wherein the first measurement determines an uncorrected concentration of a target analyte that is not corrected for interference; analyzing the sample with a second measurement, wherein the second measurement determines a concentration of an interference indicator; and applying data from the second measurement to data from the first measurement to determine a corrected concentration of the target analyte that is corrected for interference.

[0026] On the other hand, this disclosure provides at least one method for correcting interference in an assay, the method comprising the steps of: analyzing a sample with a first assay, wherein the first assay is performed to determine an initial target analyte concentration in the sample; analyzing the sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the sample; and applying data from the second assay to data from the first assay to determine a final target analyte concentration corrected for interference.

[0027] In some embodiments relating to the foregoing aspects, the target analyte is one or more electrolytes. In some embodiments, the target analyte is potassium. In some embodiments, the target analyte is an enzyme. In some embodiments, the target analyte is lactate dehydrogenase (LDH).

[0028] In some embodiments relating to the foregoing, the interference indicator is hemoglobin. In some embodiments, the concentration of hemoglobin is determined using lipemia, jaundice, and hemolysis (LIH) assays.

[0029] In another aspect, the disclosure of this technology provides at least one method for treating a patient suspected of having an electrolyte imbalance, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes.

[0030] On the other hand, this disclosure provides a method for treating a patient suspected of having an electrolyte imbalance, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial concentration of one or more electrolytes; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final concentration of the one or more electrolytes corrected for interference; and reporting the final concentration of the one or more electrolytes.

[0031] In some embodiments relating to the foregoing aspects, the method further includes the step of determining a treatment plan for the patient after reporting the corrected concentrations of the one or more electrolytes. In some embodiments, the method further includes the step of treating the patient's electrolyte imbalance with the treatment plan after determining the treatment plan for the patient.

[0032] In some embodiments relating to the foregoing aspects, the one or more electrolytes comprise potassium. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining a linear combination of the optical density (OD) of the blood sample at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variants include lipemia and bilirubin. In some other embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variants include instrument-induced variants.

[0033] In some embodiments relating to the foregoing, the step of applying the data further includes applying a correction factor to determine a corrected electrolyte concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected electrolyte concentration to determine the corrected electrolyte concentration.

[0034] In some embodiments relating to the foregoing aspects, the reporting step further includes reporting the uncorrected electrolyte concentration. In some embodiments, the reporting step includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected electrolyte concentration and the corrected electrolyte concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration.

[0035] In some embodiments relating to the foregoing aspects, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate, or combinations thereof. In some embodiments, the treatment plan of the currently described technology is used to treat hyperkalemia. In some embodiments, the treatment plan of the currently described technology is used to treat hypokalemia masked by interference.

[0036] On the other hand, the disclosure of this technology provides at least one method for treating a patient suspected of having an electrolyte imbalance, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration.

[0037] In another aspect, the disclosure of this technology provides at least one method for treating a patient suspected of having an electrolyte imbalance, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial concentration of one or more electrolytes in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the final electrolyte concentration and the initial electrolyte concentration with the reporting threshold; and if the difference between the final electrolyte concentration and the initial electrolyte concentration is greater than the reporting threshold, reporting both the final electrolyte concentration and the initial electrolyte concentration.

[0038] In some embodiments relating to the foregoing aspects, the method further includes the steps of determining whether the patient suffers from hemolytic disease and determining a treatment plan for the patient after reporting the concentrations of the one or more electrolytes. In some embodiments, the method further includes the step of treating the patient's electrolyte imbalance with the treatment plan after determining the treatment plan for the patient.

[0039] In some embodiments relating to the foregoing aspects, the one or more electrolytes comprise potassium. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises the step of quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantification comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises the step of determining a linear combination of the optical density (OD) of the blood sample at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variants include lipemia and bilirubin. In some other embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variants include instrument-induced variants.

[0040] In some embodiments relating to the foregoing, the step of applying the data further includes applying a correction factor to determine a corrected electrolyte concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and subsequently subtracting the interference magnitude from the uncorrected electrolyte concentration to determine the corrected electrolyte concentration.

[0041] In some embodiments relating to the foregoing, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0042] On the one hand, the disclosure of this technology also provides at least one method for treating a patient suspected of having hyperkalemia, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines the concentration of an interference indicator; applying data from the first assay to data from the second assay to determine a corrected potassium concentration, wherein the corrected potassium concentration is corrected for interference; and reporting the corrected potassium concentration.

[0043] On the other hand, the disclosure of this technology provides at least one method for treating a patient suspected of having hyperkalemia, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine the concentration of an interfering indicator in the blood sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for the interference; and reporting the final potassium concentration.

[0044] On the other hand, the disclosure of this technology provides at least one method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines the concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected potassium concentration, wherein the corrected potassium concentration is corrected for interference; and reporting the corrected potassium concentration.

[0045] In another aspect, the disclosure of this technology provides at least one method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient does not have hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine the concentration of an interference indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference; and reporting the final potassium concentration.

[0046] In some embodiments relating to the foregoing aspects, the method further includes the step of determining a treatment plan for the patient after reporting the corrected potassium concentration. In some embodiments, the method further includes the step of treating the patient's hyperkalemia with the treatment plan after determining the treatment plan for the patient.

[0047] In some embodiments relating to the foregoing aspects, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further includes the step of quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination includes measuring optical density at two or more wavelengths. In some embodiments, the quantitative determination further includes the step of determining a linear combination of the optical density (OD) of the blood sample at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variants include lipemia and bilirubin. In some other embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variants include instrument-induced variants.

[0048] In some embodiments relating to the foregoing, the step of applying the data further includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the step of applying the data further includes the steps of: multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0049] In some embodiments relating to the foregoing aspects, the report further includes the step of reporting the uncorrected potassium concentration. In some embodiments, the report further includes the step of reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration. In some embodiments relating to the foregoing aspects, the method of the present technology further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, then reporting both the corrected potassium concentration and the uncorrected potassium concentration.

[0050] On the other hand, this disclosure provides at least one method for treating a patient suspected of having hyperkalemia, wherein the patient is suspected of having a hemolytic condition, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of potassium that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of potassium, wherein the corrected potassium concentration is corrected for interference; and reporting an electrolyte dataset, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and reporting both the corrected potassium concentration and the uncorrected potassium concentration if the difference in the corrected potassium concentration is greater than the reporting threshold.

[0051] On the other hand, this disclosure provides at least one method for treating a patient suspected of having hyperkalemia, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration; analyzing the blood sample with a second assay, wherein the second assay is performed to determine the concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration, wherein the final potassium concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the final electrolyte concentration and the initial electrolyte concentration with the reporting threshold; and if the difference between the final electrolyte concentrations is greater than the reporting threshold, reporting both the final electrolyte concentration and the initial electrolyte concentration.

[0052] In another aspect, this disclosure provides at least one method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient is suspected of having a hemolytic condition, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of potassium that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of potassium, wherein the corrected potassium concentration is corrected for interference; and reporting an electrolyte dataset, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and reporting both the corrected potassium concentration and the uncorrected potassium concentration if the difference in the corrected potassium concentration is greater than the reporting threshold.

[0053] In another aspect, the disclosure of this technology provides at least one method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient is suspected of having a hemolytic condition, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration; analyzing the blood sample with a second assay, wherein the second assay is performed to determine the concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration, wherein the final potassium concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the final electrolyte concentration and the initial electrolyte concentration with the reporting threshold; and if the difference between the final electrolyte concentrations is greater than the reporting threshold, reporting both the final electrolyte concentration and the initial electrolyte concentration.

[0054] In some embodiments relating to the foregoing aspects, the method further includes the steps of determining whether the patient has a hemolytic condition and determining a treatment plan for the patient after reporting electrolyte concentrations. In some embodiments, the method further includes the step of treating the patient's interference-masked hypokalemia with the treatment plan after determining the treatment plan for the patient.

[0055] In some embodiments relating to the foregoing aspects, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further includes the step of quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination includes measuring optical density at two or more wavelengths. In some embodiments, the quantitative determination further includes the step of determining a linear combination of the optical density (OD) of the blood sample at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variants include lipemia and bilirubin. In some other embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variants include instrument-induced variants.

[0056] In some embodiments relating to the foregoing, the step of applying the data further includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the step of applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0057] In some embodiments relating to the foregoing, the report further includes the step of reporting the uncorrected potassium concentration. In some embodiments, the report includes the step of reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration.

[0058] In some embodiments relating to the foregoing, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0059] On the other hand, the disclosure of this technology provides at least one method for determining the necessity of a second blood draw, wherein the method includes the steps of: collecting a first blood sample using a first blood draw; analyzing the first blood sample by a assay to determine the concentration of hemoglobin; establishing a re-draw threshold; comparing the concentration of hemoglobin with the re-draw threshold; and if the concentration of hemoglobin is greater than the re-draw threshold, collecting a second blood sample using a second blood draw.

[0060] In some embodiments relating to the foregoing, establishing a re-extraction threshold further includes the steps of: (i) establishing a correction factor uncertainty; (ii) establishing a measurement target error threshold; and (iii) calculating a re-extraction threshold based on the correction factor uncertainty and the measurement target error threshold.

[0061] In some embodiments relating to the foregoing aspects, the assay is a lipidemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further includes the step of quantitatively determining the concentration of hemoglobin using the LIH assay, wherein the quantification includes measuring optical density at two or more wavelengths. In some embodiments, the quantification step further includes the step of determining a linear combination of the optical density (OD) of the blood sample at at least two or more wavelengths. In some embodiments, the quantification step further includes the step of generating one or more covariance matrices associated with substances that may interfere with hemoglobin quantification.

[0062] On the other hand, the disclosure of this technology provides a clinical chemistry instrument comprising at least the following steps: a first assay system configured to determine an uncorrected potassium concentration not corrected for interference, the first assay system including a first sensor; and a second assay system configured to determine the concentration of an interference indicator, the second assay system including a second sensor; and a processor configured to receive data from the first sensor and the second sensor to determine a corrected potassium concentration corrected for interference.

[0063] In another aspect, the present invention discloses a clinical chemistry instrument comprising at least the following steps: a first assay system configured to determine an initial potassium concentration, the first assay system including a first sensor; a second assay system configured to determine the concentration of an interfering indicator, the second assay system including a second sensor; and a processor configured to receive data from the first sensor and the second sensor to determine a final potassium concentration corrected for the interference.

[0064] In some embodiments relating to the foregoing, the corrected potassium concentration is corrected for interference without requiring further measurement or processing beyond the clinical chemistry instrument itself.

[0065] In some embodiments relating to the foregoing aspects, the interference indicator is hemoglobin. In some embodiments, the first assay system is configured to perform an ion-selective electrode (ISE) assay. In some embodiments, the second assay system is configured to perform a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the second assay system is configured to quantitatively determine the concentration of the interference indicator, wherein the quantification includes the step of measuring optical density at two or more wavelengths using the first instrument. In some embodiments, the processor is configured to apply the data received from the second sensor to the data received from the first sensor to determine the corrected potassium concentration. In some embodiments, the processor is configured to apply the data received from the second sensor to the data received from the first sensor to determine the final potassium concentration. In still further embodiments, the quantification further includes the step of determining a linear combination of optical density (OD) of the biological sample at two or more wavelengths. Furthermore, in some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of the biological sample, the multicolor OD minimizing the effects of non-hemoglobin variant sources, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variant sources in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variant sources include lipemia and bilirubin. In some other embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variant sources include instrument-induced variants. In some embodiments, the step of applying the data includes applying a correction factor. In some embodiments, the step of applying the data further includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subsequently subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the step of applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subsequently subtracting the interference magnitude from the initial potassium concentration to determine the final potassium concentration.

[0066] Various aspects and embodiments of this disclosure include, but are not limited to, systems, methods, apparatuses, components and / or software for implementing the various functions and processes described herein. Attached Figure Description

[0067] Various aspects and embodiments of this disclosure are shown in the accompanying drawings, and described therein and elsewhere throughout the disclosure. In all the drawings, the same reference numerals denote the same parts.

[0068] Figure 1 A flowchart of an example method according to this disclosure is provided.

[0069] Figure 1B A flowchart of an example method according to this disclosure is provided.

[0070] Figure 2 The spectral components of lipids are shown.

[0071] Figure 3 The spectral components of bilirubin are shown.

[0072] Figure 4 The spectral components of hemoglobin are shown.

[0073] Figure 5 This demonstrates the quantification of hemoglobin in the presence of lipemia, without the presence of bilirubin and hemoglobin.

[0074] Figure 6 This demonstrates the quantification of hemoglobin in the presence of bilirubin in the absence of lipemia and hemoglobin.

[0075] Figure 7 This demonstrates the quantification of hemoglobin in the presence of hemoglobin in the absence of lipemia and bilirubin.

[0076] Figure 8 The correction factors for 20 donor samples are shown.

[0077] Figure 9 The results show uncorrected, corrected, and non-hemolyzed potassium levels.

[0078] Figure 10 An example visual representation is shown for determining the re-sampling threshold. Detailed Implementation

[0079] Clinical assays can be affected by interference from many sources. Interference can cause reported results to be higher or lower than those in the absence of interference. Spectroscopic assays are an example of clinical assays. Spectroscopic assays typically involve a chemical reaction that forms a chromophore, the optical density (OD) of which is measured at a selected wavelength. Those skilled in the art will understand that, for the purposes of this disclosure, optical density is synonymous with absorbance. Interference in these types of assays can originate from several sources. For example, interference may be caused by substances other than the chromophore that absorb light at the monitored wavelength. Interference may also be caused by interfering substances that disrupt the chemical reaction that produces the chromophore. Interfering substances can react directly with the analyte measured by the assay, with intermediates that produce the chromophore, or with the chromophore itself.

[0080] In some instances, there may be interfering measurable or quantifiable indicators. Some examples of this include interference caused by physical conditions and / or sample handling. Aspects of this disclosure include methods and systems for correcting for this type of interference. For example, some clinical assays measure the level of an analyte in serum or plasma. However, the same analyte may be present in blood cells at different levels. Some of these cells may be lysed by physical conditions, such as the blood draw process or post-draw sample handling. Lysed cells release their contents into the extracellular fluid, thereby altering the analyte level.

[0081] Red blood cells (erythrocytes, or RBCs) are particularly prone to lysis. RBC lysis, known as hemolysis, is commonly caused by venipuncture procedures. Blood typically travels at high speed through a small-diameter needle. For example, a 22-gauge needle has an inner diameter of 0.413 mm. If 5 mL of blood is drawn into a test tube in 5 seconds, the blood will travel through the needle at 4.8 m / s. This generates considerable turbulence and shear forces, putting stress on the RBCs and potentially leading to hemolysis. Although much has been written about venipuncture procedures and other sample handling procedures to minimize hemolysis, it remains common. Difficult blood draws, especially when smaller diameter needles are required, increase the risk of hemolysis. This is particularly prevalent in the emergency department, where patients may be dehydrated and in serious condition.

[0082] Potassium, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and magnesium are common examples of analytes that are measured at higher levels in RBCs than in serum or plasma. Therefore, hemolysis increases the levels of these analytes that are subsequently measured.

[0083] Hemolysis interference is particularly significant in assays used to measure potassium. Potassium levels in RBCs are approximately 30 times higher than in serum or plasma, resulting in a potentially large impact of hemolysis on reported potassium concentrations. Furthermore, hyperkalemia or hypokalemia can be medical emergencies involving dangerous arrhythmias or even cardiac arrest. In the presence of hemolysis, clinicians may struggle to distinguish between high potassium levels caused by hemolysis (pseudohyperkalemia) and high potassium levels in the absence of hemolysis (hyperkalemia). While EKG is a rapid test and can sometimes aid in definitive diagnosis, waiting for re-drawing can be lengthy, and time is often a critical factor in these situations. Therefore, there is not always sufficient time to re-draw and reanalyze blood, and clinicians must make treatment decisions based on available data that may be affected by hemolytic interference. Therefore, aspects of this disclosure include one or more methods for correcting potassium results for interference from hemolysis. Those skilled in the art will understand that the disclosed methods and systems can be applied to other analytes subjected to interference, whether from hemolysis or other sources of interference.

[0084] Hemolytic interference can occur regardless of the analytical technique used to measure the analyte. This is because hemolysis can release the analyte into the surrounding fluid, making it impossible to distinguish between the portion of the analyte present in the fluid prior to hemolysis and the portion released by hemolysis. However, for some analytes, the amount of hemoglobin in the fluid can be a suitable indicator of the amount of excess analyte due to hemolysis. Therefore, mathematical corrections for hemolysis can be made to analyte levels based on measurements of hemoglobin levels. Although hemoglobin is described as an indicator of hemolysis, it must be understood that other analytes released from RBCs via hemolysis can also be used as indicators of hemolysis (e.g., LDH and AST).

[0085] The example methods disclosed in this technology include mathematical corrections that rely on the following three factors: 1) the hemoglobin in serum or plasma is due to in vitro hemolysis rather than in vivo hemolysis; 2) accurate hemoglobin quantification; and 3) the analyte:hemoglobin ratio within RBCs is consistent among patients.

[0086] Various assays can be used to measure analytes, such as potassium. For example, an ion-selective electrode (ISE) assay can be used to measure the analyte. In other instances, analytes (e.g., potassium, LDH, or AST) can be measured by spectroscopic methods. Various assays can be used to measure interfering indicators. For example, a serum index (LIH) assay can be used to measure hemoglobin. LIH assays are routinely performed, especially when interfering substances are suspected in the sample. Therefore, hemoglobin measurements are usually available and no additional assay is required. Those skilled in the art will understand that different assays can be performed at different times and / or require different time lengths to complete.

[0087] LIH assays are generally considered semi-quantitative and therefore not precise enough to be reliably used in correction processes for interference. Aspects of this disclosure include methods and systems for quantitatively measuring interfering indicators (such as hemoglobin) using LIH assays. This quantification, which incorporates raw optical density data at several wavelengths, can be used to accurately quantify hemoglobin. Furthermore, the quantification of hemoglobin can be designed to minimize the influence of other common interfering agents (such as bilirubin and lipemia). Therefore, aspects of this disclosure include methods for quantifying hemoglobin using LIH data in conjunction with other analytes, said methods being performed in a manner that minimizes interference from interfering agents (such as bilirubin and lipemia). This is particularly important for newborns who frequently present with jaundice.

[0088] Those skilled in the art will further understand that clinical expertise, including, for example, a review of the patient's medical history, is required to differentiate between in vivo hemolysis caused by a patient with a hemolytic disorder and the more common in vitro hemolysis. Therefore, aspects of the currently described technique include reporting corrected analyte (e.g., potassium) concentrations, uncorrected analyte concentrations, or both corrected and uncorrected analyte concentrations, based on various clinical factors. Although, as stated above, different assays may be performed at different times, the advantage of the method according to the disclosure of this technique includes reporting corrected results, such as calculated results, to the clinician simultaneously with uncorrected results.

[0089] Methods for analyzing biological samples

[0090] On one hand, the disclosure of this technology provides methods for analyzing biological samples (such as blood samples, urine samples, tissue samples, and saliva samples). The methods according to this disclosure include analyzing biological samples, such as blood samples, to determine the concentration of a target analyte. The target analyte may include, for example, electrolytes, proteins, enzymes, small molecules, and other biologically relevant molecules. For illustration, the target analyte may include, for example, potassium, sodium, or chloride. In other examples, the target analyte may be lactate dehydrogenase (LDH). In yet another example, the target analyte may be aspartate aminotransferase (AST).

[0091] In some embodiments, the method of this technology may be a method for analyzing blood samples to determine the concentration of one or more electrolytes, the concentration being corrected for interference. For example, the method according to the disclosure of this technology includes a method for analyzing blood samples to determine a potassium concentration corrected for interference. In other embodiments, this disclosure provides a method for determining potassium imbalance. In further instances, this disclosure provides a method for improving the determination of potassium concentration in biological samples, a method for indicating whether a patient has an electrolyte imbalance, or a method for correcting for interference in a measurement.

[0092] As described above, the method according to this disclosure includes a method for determining a potassium concentration corrected for interference, and a method for improving the determination of potassium concentration in a biological sample. The method may include analyzing a blood sample using one or more assays. For example, the biological sample may be analyzed using a first assay and a second assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample, and wherein the second assay is performed to determine the concentration of an interfering indicator in the blood sample. The method may further include applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference. Thus, the final potassium concentration may be a corrected potassium concentration.

[0093] As described above, the method according to this disclosure includes a method for indicating whether a patient has an electrolyte imbalance (e.g., potassium imbalance), the method comprising the step of collecting at least one biological sample (e.g., a blood sample) from the patient. The method may further comprise analyzing the blood sample using one or more assays. For example, the biological sample may be analyzed using a first assay and a second assay, wherein the first assay is performed to determine an initial target analyte concentration in the biological sample, and wherein the second assay is performed to determine the concentration of an interfering indicator in the biological sample. The target analyte may comprise various molecules, such as electrolytes, proteins, enzymes, small molecules, or other biologically relevant molecules. In some instances, the target analyte comprises one or more electrolytes, such as potassium, sodium, or chloride. The method may further comprise the step of applying data from the second assay to data from the first assay to determine a target analyte concentration corrected for interference. In some embodiments, the method further comprises reporting the final target analyte concentration. Therefore, in some embodiments, the method according to this disclosure may, for example, include the following steps: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected electrolyte concentration.

[0094] In some embodiments, the method for indicating whether a patient has an electrolyte imbalance may further include, after reporting the corrected electrolyte concentration, a step of indicating whether the corrected electrolyte concentration is higher or lower than an electrolyte imbalance threshold. The electrolyte imbalance threshold may be determined based on the clinical significance of the measured electrolyte concentration to the patient (e.g., medical history, medication, hydration status, and other clinical observations and factors). In some embodiments, the reporting step may further include reporting an uncorrected electrolyte concentration in addition to reporting the corrected electrolyte concentration. In other embodiments, the reporting may include reporting a comparison between the uncorrected electrolyte concentration and the corrected electrolyte concentration. In some embodiments, what is reported may depend on the comparison between the corrected electrolyte concentration and the uncorrected electrolyte concentration with a reporting threshold. For example, in some embodiments, the method for indicating whether a patient has an electrolyte imbalance may further include the steps of: (i) establishing a reporting threshold; (ii) comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and (iii) if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration. In some embodiments, the reporting threshold may be based on clinically significant difference or total tolerance. Those skilled in the art will understand that various total tolerances can be utilized. For example, the total tolerance for potassium may be 0.2 mmol / L (Royal College of Pathologists Australia (RCPA)), 0.5 mmol / L (CLIA '88, Clinical Laboratory Improvement Amendments (CLIA), College of American Pathologists (CAP)), 5.8% (2004 update of the Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC) Ideal Quality Specification Table based on biological variation), 6% (fixed limit of the Saskatchewan College of Physicians and Surgeons (CFX) of Canada), 5.0% (EFLM European Federation of Clinical Chemistry and Laboratory Medicine), or 4.1% (EFLM median CV estimate). Total tolerances can be determined using methods understood by those skilled in the art. See, for example, CLSI EP21 ED2:2016. In some embodiments, the report may include steps for reporting uncorrected electrolytes and annotations. The content of the annotations may depend on various factors, such as clinician or laboratory policies or preferences. For example, a note may report the difference between an uncorrected electrolyte concentration and a corrected electrolyte concentration. In some embodiments, a note may report an uncorrected electrolyte concentration and a note indicating the presence of hemolysis. In some embodiments, a note may report an uncorrected electrolyte concentration and a note indicating that hemolysis is present along with the corrected electrolyte concentration. In some embodiments, the amount of excess potassium induced by hemolysis may be reported as a range based on the uncertainty of a correction factor, which may be determined as described herein.

[0095] In some embodiments, data from one or more assays can be received and applied by a processor. For example, a method for analyzing a biological sample may include analyzing a blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample, and receiving data corresponding to the initial potassium concentration at a processor. The method may further include analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; and receiving data corresponding to the concentration of the interfering indicator at the processor. After the processor receives data from each assay, the method may further include the processor determining a final potassium concentration corrected for interference, wherein the final potassium concentration is determined by applying data from the second assay to data from the first assay. Therefore, in some embodiments, the method according to this disclosure may include, for example, the following steps: analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; receiving data corresponding to the initial potassium concentration at a processor; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; and receiving data corresponding to the concentration of the interfering indicator at the processor; and determining a final potassium concentration corrected for the interference by the processor, wherein the final potassium concentration is determined by applying data from the second assay to data from the first assay.

[0096] Based on the disclosure of the currently described art, various types of assays can be incorporated into the method. For example, as described above, in some embodiments, a method for analyzing a biological sample may include analyzing the biological sample with a first assay, wherein the first assay is performed to determine an uncorrected (or initial) concentration or one or more target analytes. For example, the first assay may be performed to determine the uncorrected concentration of one or more electrolytes (such as potassium, sodium, or chloride). In some embodiments, the first assay may be an ion-selective electrode (ISE) assay. In some embodiments, the first assay may be an assay for determining the concentration of other target analytes subjected to interference (such as aspartate aminotransferase (AST) or lactate dehydrogenase (LDH)). In some embodiments, the method may include analyzing the biological sample with an ISE assay, wherein the ISE assay is performed to determine the initial concentration of one or more electrolytes, such as an initial potassium concentration. In some embodiments, the initial potassium concentration is an uncorrected potassium concentration not corrected for interference.

[0097] As described above, the methods according to this disclosure may include methods for correcting for interference. In some embodiments, the interference indicator may comprise a small molecule, protein, enzyme, or other entity that may interfere with the determination of the target analyte. For example, in some embodiments, the interference may be hemoglobin.

[0098] Depending on the nature of the interfering indicator, various types of assays can be used to measure its concentration. As described above, in some embodiments of this technology, a method for analyzing a biological sample may include, for example, analyzing the biological sample with a second assay, wherein the second assay is performed to determine the concentration of the interfering indicator in the biological sample. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In another embodiment, the interfering indicator may be hemoglobin, and a LIH assay is performed to determine the concentration of hemoglobin in the biological sample. In some embodiments, the assay may be a serum hemoglobin assay.

[0099] In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using a LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. For example, in some embodiments, the quantitative determination comprises measuring optical density at up to 2, 5, 8, 10, 20, 50, 100, 200, or 500 wavelengths. In some embodiments, the quantitative determination comprises measuring optical density at 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 wavelengths. In some embodiments, the quantitative determination comprises measuring optical density at seven wavelengths ranging from 340 nm to 540 nm (e.g., 340 nm, 380 nm, 410 nm, 450 nm, 480 nm, 520 nm, and 540 nm).

[0100] The quantification step may further include applying a linear combination of the optical density (OD) of the sample at two or more wavelengths. In another example, the quantification step may further include generating one or more covariance matrices associated with substances that may interfere with the quantification of the indicator. For example, the quantification may further include generating one or more covariance matrices associated with sources of variation in hemoglobin optical density measurements that are not caused by changes in hemoglobin concentration.

[0101] Therefore, in some embodiments, the quantitative determination includes determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variant sources. Determining the multicolor OD may include the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variant sources in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector can then be applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, non-hemoglobin variant sources include lipemia and bilirubin. In some other embodiments, generating the covariance matrix includes adding irrelevant variants (referred to as "regularization" by those skilled in the art) to the covariance matrix. Furthermore, in some other embodiments, the non-hemoglobin variant sources include instrument-induced variants. Example 1 describes an example procedure for quantitatively determining hemoglobin in a biological sample from optical density (OD) data, based on the disclosure of this technology.

[0102] As discussed above, one or more methods according to the disclosure of this technology may include applying data from a second assay to data from a first assay to determine a final target analyte concentration (e.g., one or more electrolytes, such as potassium). The final electrolyte concentration may be a corrected electrolyte concentration corrected for interference. Therefore, in some embodiments, the method includes applying data from a second assay to data from a first assay to determine a corrected potassium concentration, wherein the corrected potassium concentration is corrected for interference. Applying the data may include applying a correction factor to determine the corrected potassium concentration. In some embodiments, applying the data further includes the steps of: (i) multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and (ii) subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. The correction factor may be determined based on various factors, including clinical data and others. This can be mathematically expressed as an equation. ,in and These are the corrected potassium concentration and the uncorrected potassium concentration, respectively. It is the concentration of the interfering indicator, and It is a correction factor.

[0103] In some embodiments, the correction may depend on whether a positive or negative interference is involved. For example, a positive interference may be caused by an intraerythrocyte electrolyte concentration higher than the serum electrolyte concentration, leading to hemolysis and resulting in excess electrolytes in the serum. Inter-patient variability may be represented as an excess electrolyte range, which can be calculated by multiplying the correction factor range by the hemoglobin concentration. The uncertainty of the estimated excess electrolyte concentration (which may be equal to the uncertainty of the corrected target analyte concentration) can be calculated as the larger difference between the estimated excess concentration and the limit of the excess electrolyte range. In some instances, the correction factor range may represent 2.5% to 97.5% of patient samples. In some instances, the correction factor may be the midpoint of the correction factor range or the 50th percentile of the patient sample. In some embodiments, the excess electrolyte range may provide a correction range that can be subtracted from the uncorrected electrolyte concentration. Example 2 describes an example procedure for determining a correction factor according to the disclosure of this technology. As shown in Example 2, aspects of this disclosure include determining a correction factor with low inter-patient variability. Another exemplary procedure is described in van Rossum, 2021, Clinica Chimica Acta 522:83-87.

[0104] Figure 1 A flowchart illustrating an example method according to this disclosure is shown. Figure 1 Online process 170 and offline processes 175 and 190 are shown. (For example...) Figure 1As shown, biological sample 105 can be analyzed using a first assay 110 and a second assay 115. Interference correction 130 can be determined by applying data from the first assay 110 to data from the second assay 115. For this purpose, the second assay 115 can be configured to, for example, quantitatively determine the concentration of interfering indicators as described herein. Quantitative determination may include wavelength selection 125 and measurements of a single absorption spectrum or two or more absorption spectra, including, for example, hemoglobin absorption spectrum 140, lipemia absorption spectrum 145, bilirubin absorption spectrum 150, and optionally other sources of variation 155. In some instances, quantitative determination may include wavelength selection and measurements of a single absorption spectrum (e.g., hemoglobin spectrum). In some instances, quantitative determination may include wavelength selection 125 and measurements of two or more absorption spectra. In some instances, covariance matrix 160 can be created from lipemia absorption spectrum 145, bilirubin absorption spectrum 150, and optionally other sources of variation 155. Multicolor OD 165 can be determined by covariance matrix 160 and hemoglobin absorption spectrum 140, and is used to quantitatively determine the concentration of interference indicator (e.g., hemoglobin concentration). The quantitative interference indicator concentration can then be applied to data from first assay 110 to determine the corrected target analyte (e.g., potassium) concentration via interference correction 130 as described herein. Interference correction 130 further includes the application of correction factors as described herein. For this purpose, at process 190, clinical data 180 can be analyzed to determine correction factor 185. Data from this process can then be reported at report 135. Figure 1B As shown, the hemoglobin absorption spectrum 140 can be characterized at 195 using the extinction coefficient vector (a) 215, which characterizes the hemoglobin spectrum. Further, at 200, the lipemia absorption spectrum 145, bilirubin absorption spectrum 150, and other variation sources 155 (collectively referred to as non-hemoglobin variation sources) can be characterized using the covariance matrix (V) 160 associated with non-hemoglobin variation sources. The polychromatic vector (k) 205, which is a function of the extinction coefficient vector 215 and the covariance matrix 160, can then be determined. The polychromatic OD 165 is then determined from the polychromatic vector (k) 205 and the measured optical density 210. Example 1 describes an example procedure for quantitatively determining hemoglobin in a biological sample from optical density (OD) data according to the disclosure of this technique.

[0105] Treatment

[0106] On one hand, the disclosure of this technology provides one or more methods for treating patients, including the methods for analyzing biological samples described above. For example, methods according to the disclosure of this technology include, for example, one or more methods for treating patients suspected of having electrolyte imbalances. In some embodiments, the treatment method may be a method for treating patients suspected of having hyperkalemia or a method for treating patients suspected of having hypokalemia. In some embodiments, the treatment method may be a method for treating patients suspected of having hyperkalemia or hypokalemia masked by interference (e.g., hemolytic interference). In some embodiments, the patient does not have a hemolytic disease. In some embodiments, the patient is suspected of having a hemolytic disease. Hemolytic diseases may include hereditary hemolytic anemias such as sickle cell disease, thalassemia, erythrocyte membrane disorders (e.g., hereditary spherocytosis, hereditary elliptic polycythemia, hereditary eosinophilia, hereditary oral polycythemia, and hereditary exocytosis), pyruvate kinase deficiency (PKD), and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Hemolytic disorders can also include acquired hemolytic anemias such as immune hemolytic anemia, autoimmune hemolytic anemia (AIHA), alloimmune hemolytic anemia, drug-induced hemolytic anemia, mechanical hemolytic anemia, paroxysmal nocturnal hemoglobinuria (PNH), malaria, babesiosis, and other infectious anemias. Intra-in vivo hemolysis can also be caused by medical procedures (e.g., dialysis) or trauma (e.g., foot strike while running). In such cases, the patient does not have a hemolytic disease, but the hemolysis reflects the condition within the patient's body, contrasting with in vitro hemolysis, where the hemolysis is inconsistent with the patient's internal condition.

[0107] In some embodiments, the method according to this disclosure includes collecting at least one biological sample (e.g., a blood sample) from a patient. As discussed in detail above, the method of this technology may include analyzing the blood sample using one or more assays. For example, the biological sample may be analyzed using a first assay and a second assay, wherein the first assay is performed to determine an initial concentration of one or more electrolytes (e.g., potassium) in the biological sample, and wherein the second assay is performed to determine the concentration of interfering indicators (e.g., hemoglobin) in the biological sample. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the LIH assay may quantitatively determine the hemoglobin concentration. As discussed in detail above, such quantitative determination may include, for example, measuring optical density at two or more wavelengths.

[0108] Therefore, in some embodiments, the quantitative determination includes determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants. Determining the multicolor OD may include the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector can then be applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, wherein the multicolor OD is proportional to the hemoglobin concentration. Example 1 describes an example procedure for quantitatively determining hemoglobin in a biological sample from optical density (OD) data according to the disclosure of this technique.

[0109] The method may further include applying data from the second measurement to data from the first measurement to determine a final concentration of the one or more electrolytes corrected for interference. In some embodiments, the method further includes reporting the final concentration of the one or more electrolytes. Thus, in some embodiments, the method according to the disclosure of this technology may, for example, include: collecting at least one blood sample from the patient; analyzing the blood sample with a first measurement, wherein the first measurement determines an uncorrected concentration of one or more electrolytes not corrected for interference; analyzing the blood sample with a second measurement, wherein the second measurement determines a concentration of an interference indicator; applying data from the second measurement to data from the first measurement to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected electrolyte concentration.

[0110] In some embodiments, a treatment plan for the patient is determined after the final or corrected concentrations of the one or more electrolytes are reported. Various treatment methods may be employed as part of the treatment plan. The treatment plan may include any treatment deemed appropriate by a clinician for electrolyte imbalance, hyperkalemia, and / or hypokalemia. (Viera, AJ et al., Potassium Disorders: Hypokalemia and Hyperkalemia, *American Fam Physician* 2015;92(6):487-495.) In some embodiments, the treatment plan may include hemodialysis or administration of at least one of the following: oral rehydration salts (ORS) solution, oral potassium, intravenous (IV) fluids, IV electrolyte (e.g., potassium) infusion, diuretics, blood pressure medications (e.g., angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), beta-blockers), potassium binders, insulin, sympathomimetic drugs, potassium-sparing diuretics, or calcium gluconate or combinations thereof. Alternatively or concurrently, the treatment plan may include stopping or reducing the dosage of medications, including, for example, diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, calcium gluconate, nonsteroidal anti-inflammatory drugs (NSAIDs), heparin, lithium, calcineurin inhibitors, or combinations thereof. After determining the treatment plan for the patient, the treatment plan can be used to treat the patient's electrolyte imbalance. The treatment plan can be used to treat conditions, symptoms, or signs associated with electrolyte imbalance. For example, in some embodiments, the treatment plan is used to treat hyperkalemia. In other embodiments, the treatment plan is used to treat hypokalemia masked by interference.

[0111] Treatment plans can be determined based on data from one or more measurements described above. In some embodiments, treatment plans can be determined by the final or corrected concentrations of one or more electrolytes. In some embodiments, treatment plans can be determined based on the initial or uncorrected concentrations of one or more electrolytes. In some embodiments, treatment plans can be determined based on a combination of the initial (or uncorrected) and final (or corrected) concentrations of one or more electrolytes. Those skilled in the art will understand that other factors, such as the patient's medical history, current signs and symptoms, and test and laboratory results, will also be considered when determining a treatment plan.

[0112] As described above, applying data from a first measurement to data from a second measurement may include applying a correction factor to determine a corrected electrolyte concentration. In some embodiments, the step of applying the data may include the additional steps of (i) multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and (ii) subsequently subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0113] In some embodiments, a method of treating a patient according to the disclosure of this technology may further include a step of indicating whether the corrected electrolyte concentration is higher or lower than an electrolyte imbalance threshold after reporting the corrected electrolyte concentration. The electrolyte imbalance threshold may be determined based on the clinical significance of the measured electrolyte concentration to the patient. In some embodiments, in addition to reporting the corrected electrolyte concentration, the reporting may further include reporting an uncorrected electrolyte concentration. In some embodiments, what is reported may depend on a comparison between the corrected and uncorrected electrolyte concentrations and a reporting threshold. For example, in some embodiments, a method of indicating whether a patient has an electrolyte imbalance may further include the steps of: (i) establishing a reporting threshold; (ii) comparing the difference between the corrected and uncorrected electrolyte concentrations with the reporting threshold; and (iii) reporting both the corrected and uncorrected electrolyte concentrations if the difference in the corrected electrolyte concentrations is greater than the reporting threshold. In some embodiments, the reporting threshold may be based on a clinically significant difference or a total tolerance error. Those skilled in the art will understand that various total tolerance errors can be utilized. For example, the total tolerance for potassium can be 0.2 mmol / L (Royal College of Pathologists Australia (RCPA)), 0.5 mmol / L (CLIA '88, Clinical Laboratory Improvement Amendments (CLIA), College of American Pathologists (CAP)), 5.8% (2004 update of the Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC) Ideal Quality Specification Table based on biological variation), 6% (fixed limit of the Saskatchewan College of Physicians and Surgeons (CFX) of Canada), 5.0% (EFLM European Federation of Clinical Chemistry and Laboratory Medicine), or 4.1% (EFLM median CV estimate). The total tolerance can be determined using methods understood by one of ordinary skill in the art. See, for example, CLSIEP21 ED2:2016.

[0114] In some embodiments, the report may include a report of uncorrected electrolytes and annotations. For example, the annotations may report the difference between the uncorrected electrolyte concentration and the corrected electrolyte concentration.

[0115] Methods for determining the necessity of a second blood draw

[0116] On one hand, the disclosure of this technology provides one or more methods for determining the necessity of a second blood draw. Interferences (such as hemoglobin) may necessitate one or more additional blood draws before analyzing a blood sample with an assay (such as those described herein). For example, a method for determining the necessity of a second blood draw may include the steps of: collecting a first blood sample with a first blood draw; analyzing the first blood sample with an assay to determine the concentration of hemoglobin; establishing a re-draw threshold; and comparing the hemoglobin concentration with the re-draw threshold. In some embodiments, if the hemoglobin concentration is greater than the re-draw threshold, the method may further include collecting a second blood sample with a second blood draw.

[0117] In some embodiments, the re-sampling threshold may be based on the level of uncertainty of the interference. For example, the re-sampling threshold may be determined based on the point at which the uncertainty of the interference becomes clinically significant. This uncertainty can be assessed based on various factors, such as total permissible error. Those skilled in the art will understand that various total permissible errors can be utilized. For example, the total permissible error for potassium may be 0.2 mmol / L (Royal College of Pathologists of Australia (RCPA)), 0.5 mmol / L (CLIA '88, Clinical Laboratory Improvement Amendments (CLIA), College of American Pathologists (CAP)), 5.8% (2004 update of the Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC) Ideal Quality Specification Table based on biological variation), 6% (fixed limit of the Saskatchewan College of Physicians and Surgeons (CFX) of Canada), 5.0% (EFLM European Federation of Clinical Chemistry and Laboratory Medicine), and 4.1% (EFLM median CV estimate). Total permissible error can be determined using methods understood by those skilled in the art. See, for example, CLSI EP21 ED2:2016.

[0118] In some embodiments, establishing the re-sampling threshold may include the following steps: (i) establishing a correction factor uncertainty; (ii) establishing a measurement target error threshold; and (iii) calculating the re-sampling threshold based on the correction factor uncertainty and the measurement target error threshold. Example 2 describes an example procedure for determining a correction factor (including correction factor uncertainty) according to the disclosure of this technology.

[0119] Figure 10 An example visual representation of how the re-deduction threshold is determined according to this disclosure is shown. Figure 10The examples described assume a maximum permissible error of 0.2 mmol / L. For uncorrected results, the difference between the corrected and uncorrected results equals the maximum permissible error for hemolysis below 100 mg / dL. This represents the resampling threshold without correction. For corrected results, the uncertainty of the result is equivalent to the uncertainty of the correction, i.e., the difference between the corrected result and the limit of the corrected result range. This equals the maximum permissible error for hemolysis close to 500 mg / dL. This is in... Figure 10 The threshold value is displayed in the image. Those skilled in the art will understand that if the corrected result is not at the midpoint of the corrected result range, the re-sampling threshold needs to be adjusted accordingly.

[0120] In some embodiments, the determination used to analyze blood samples is a LIH determination. In some embodiments, the method further includes using the methods described in detail above to quantitatively determine the concentration of hemoglobin using a LIH determination. For example, in some embodiments, the quantification may include measuring optical density at at least two or more wavelengths. In some embodiments, the quantification may include determining a linear combination of optical densities of a sample containing hemoglobin at at least two or more wavelengths. In some embodiments, the quantification may include generating one or more covariance matrices associated with substances that may interfere with the quantification of hemoglobin. Thus, in some embodiments, the quantification includes determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants. Determining the multicolor OD may include the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector can then be applied to optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, wherein the multicolor OD is proportional to the hemoglobin concentration. Example 1 describes an example procedure for quantitatively determining hemoglobin in a biological sample from optical density (OD) data according to the disclosure of this technique.

[0121] As discussed above, in some embodiments of this technology, one or more methods may include determining an excess electrolyte range, which may be calculated as a correction factor range (e.g., as discussed above in

[0102] ) multiplied by the hemoglobin concentration. The uncertainty of the estimated excess electrolyte concentration (which is equal to the uncertainty of the corrected concentration) will be calculated as the larger difference between the estimated excess concentration and the excess electrolyte range limit. For example, if the estimated excess concentration is 0.8 mmol / L, and the excess electrolyte range limit is 0.7 mmol / L and 1.0 mmol / L, then the larger difference between the estimated excess concentration and the excess electrolyte range limit is 0.2 mmol / L. The excess electrolyte range can provide a correction range that can be subtracted from the uncorrected electrolyte concentration to produce a corrected electrolyte concentration. If the larger difference between the estimated excess electrolyte and the excess electrolyte range limit is greater than an uncertainty threshold (e.g., clinically significant difference, total tolerance error), the corrected result may be considered clinically unreliable, and a resampling must be performed. In some embodiments, the uncertainty threshold may depend on a corrected potassium concentration; for example, 4.85% biological variability. In some embodiments, the correction is proportional to the hemoglobin level, and so is the maximum difference between the estimated excess electrolyte and the limit of the excess electrolyte range. Therefore, for a given corrected potassium concentration, there may be a hemoglobin concentration threshold where the maximum difference equals the uncertainty threshold. If hemoglobin is above the hemoglobin concentration threshold, the uncertainty is greater than the uncertainty threshold, and unless the patient is known to be hemolytic, a second sample must be taken.

[0122] Clinical Chemistry Instruments

[0123] In some aspects and embodiments, the disclosure of this technology provides systems or devices, such as clinical chemistry instruments, that include one or more assay systems. Example clinical chemistry instruments according to the disclosure of this technology can be configured to determine corrected concentrations of one or more target analytes using methods for analyzing biological samples as described above. For example, a clinical chemistry instrument according to the disclosure of this technology may include: a first assay system configured to determine an initial concentration of one or more electrolytes; a second assay system configured to determine a concentration of an interfering indicator; and a processor configured to receive data and determine a final concentration of the one or more electrolytes corrected for interference. In some embodiments, the clinical chemistry instrument may include a single assay system configured to determine an initial concentration of one or more electrolytes and a concentration of an interfering indicator. In some embodiments, the clinical chemistry instrument may include: a first assay system configured to determine an initial potassium concentration, the first assay system including a first sensor; and a second assay system configured to determine the concentration of the interfering indicator, the second assay system including a second sensor; and a processor configured to receive data from the first sensor and the second sensor and determine a final potassium concentration corrected for interference. In some embodiments, the initial potassium concentration is an uncorrected potassium concentration that is not corrected for interference. In some embodiments, the final potassium concentration is a corrected potassium concentration that is corrected for interference. Therefore, an example clinical chemistry instrument may include: a first assay system configured to determine an uncorrected potassium concentration that is not corrected for interference, the first assay system including a first sensor; and a second assay system configured to determine the concentration of the interference indicator, the second assay system including a second sensor; and a processor configured to receive data from the first sensor and the second sensor and determine a corrected potassium concentration that is corrected for interference.

[0124] In some embodiments, the final or corrected potassium concentration is corrected for interference without requiring further assays beyond the clinical chemistry instrument itself. Such results provide at least one advantage of this technique over conventional systems and equipment.

[0125] The assay system according to the disclosure of this technology can also be configured to determine uncorrected (or initial) concentrations or one or more target analytes. For example, a first assay can be performed to determine the uncorrected concentration of one or more electrolytes (such as potassium, sodium, or chloride). In some embodiments, the first assay can be an ion-selective electrode (ISE) assay. In some embodiments, the first assay can be an assay for determining the concentration of other target analytes subjected to interference (such as aspartate aminotransferase (AST) or lactate dehydrogenase (LDH)).

[0126] The assay system according to this disclosure can be configured to determine the concentration of one or more target analytes and correct for interference. For example, in some embodiments of the present technology, the target analyte may be one or more electrolytes (e.g., potassium), and the interference indicator may be hemoglobin. Thus, in some embodiments, the second assay system may be configured to perform lipemia, jaundice, and hemolysis (LIH) assays. In some embodiments, the LIH assay may be configured to quantitatively determine hemoglobin concentration using the methods discussed in detail above. For example, in some embodiments, the quantitative determination may include measuring optical density at at least two or more wavelengths. In some embodiments, the quantitative determination may include determining a linear combination of the optical densities of hemoglobin at at least two or more wavelengths. In some embodiments, the quantitative determination may include generating one or more covariance matrices associated with substances that may interfere with the quantification of hemoglobin. Thus, in some embodiments, the quantitative determination includes determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variation sources. Determining the multicolor OD may include the following steps: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector can then be applied to optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, wherein the multicolor OD is proportional to the hemoglobin concentration. Example 1 describes an example procedure for quantitatively determining hemoglobin in a biological sample from optical density (OD) data according to the disclosure of this technique.

[0127] As discussed above, according to the disclosure of this technology, a clinical chemistry instrument may include a processor configured to receive data from a first sensor and a second sensor and determine a final or corrected concentration of one or more target analytes (such as potassium). In some embodiments, the processor may be configured to apply data received from the first sensor to data received from the second sensor to determine a final or corrected potassium concentration. Further, the application of data may include the methods described above. Therefore, in some embodiments, the application of the data may include applying a correction factor. In some embodiments, the application of the data further includes the steps of: (i) multiplying the concentration of the target interference indicator by a correction factor to determine the interference magnitude; and (ii) subsequently subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0128] Example

[0129] Example 1 - Quantitative Hemoglobin

[0130] A hemoglobin optical density (“OD”) unaffected by lipidemia and bilirubin interference (also referred to herein as multicolor OD) was developed. The coefficients of a linear combination of ODs at a set of wavelengths were calculated, and the coefficients of said linear combination were determined to minimize the effects of non-hemoglobin variation sources without biasing the estimation of hemoglobin. The coefficients of the linear combination were determined using the following:

[0131]

[0132] Where k is a multicolor vector, i.e., a vector of linear combination coefficients; a is an extinction coefficient vector, i.e., a vector containing the relative OD of the interfering indicator (hemoglobin); V is the covariance matrix of the non-hemoglobin variant sources, in this case, from lipemia and bilirubin interference; and T is the mathematical matrix transpose. Methods for optimizing variant sources using the above equations have been reported. See, for example, Luenberger, DG, “Optimization by VectorSpace Methods” (1969); U.S. Patent No. 5,014,216. To determine the effect of each substance / interference (i.e., hemoglobin, lipemia, or bilirubin) on the measured OD, sample groups were created. Each sample group comprised 11 different amounts of selected substances / interferences (i.e., hemoglobin, lipemia, or bilirubin), incorporated into a common serum pool, and the OD of each sample was measured in four replicates using a LIH assay on an AU 480 instrument (Beckman Coulter, Inc., Brea, CA). The following procedure was then followed.

[0133] In step (i), for each group, singular value decomposition is applied to the measured OD from the LIH measurement to determine the main spectral component and the amplitude of the main spectral component; then the main spectral component is multiplied by its amplitude to represent the typical effect of the substance / interference in the group.

[0134] In step (ii), the extinction coefficient vector characterizing the OD spectra of hemoglobin at two or more wavelengths is determined as follows: The covariance matrix associated with the sources of hemoglobin variation (groups of hemoglobin level changes between samples) is calculated from the sum of outer products of the results in step (i). The sum of outer products indicates that there are multiple groups of hemoglobin, each with its own principal components and amplitudes. The resulting sum represents the covariance due to changes in hemoglobin concentration. The principal eigenvector of the hemoglobin covariance matrix represents the OD spectrum of hemoglobin. The extinction coefficient vector (a) is proportional to the principal eigenvector of the hemoglobin covariance matrix.

[0135] In step (iii), the covariance matrix associated with non-hemoglobin sources of variation (V) (groups arising from inter-sample changes in bilirubin or lipemia levels, but where hemoglobin levels remain constant) is calculated from the sum of the outer products of the results from step (i). The sum of outer products means that there are multiple groups for each interfering substance, each with its own principal components and amplitudes. Any variability between groups may be due to factors such as the variability of the substance and the use of different analyzers. The outer product of each group will be a rank-1 covariance matrix, but when they are summed, the matrix will have a higher rank. The additional components represent the variability of the substance and the measurement. For example, lipemia does not have a precise composition but exhibits a granular distribution that may vary between groups. Therefore, the sum of outer products minimizes the effect of all groups as a whole rather than just individual groups in a linear combination. Using a covariance matrix calculated from the sum of multiple groups increases the robustness of hemoglobin quantification to changes in lipemia type or bilirubin conformation.

[0136] Figure 2 The principal, second, and third components of the lipemia effect are shown. Figure 3 The primary, secondary, and tertiary components of bilirubin are shown, and... Figure 4The principal, second, and third components of hemoglobin are shown. The principal effect corresponds to the typical spectrum of the substance. The second and third effects incorporate variability between different data sets. Hemoglobin exhibits very low variability, which is expected because it is a specific molecule with a cyclic, lock-like conformation that cannot undergo significant changes. However, bilirubin shows greater variability, particularly noteworthy for the second component at 410 nm and 480 nm. Although bilirubin is a specific molecule, it is not cyclically locked like hemoglobin, so it can exist in various geometries with slightly different spectra. Finally, lipemia is not a specific molecule; instead, its spectrum depends on the distribution of lipid particle size. This typically results in a more or less steeply sloping spectrum, as shown by the second component corresponding to the slope.

[0137] Those skilled in the art will understand that other non-hemoglobin sources of variation can be considered in the covariance matrix V. For example, variations due to the light source can be considered. However, in this case, such variations are characterized by measuring the OD of the water blank. Because the resulting covariance is too small to be considered for the purposes of this study, V is not adjusted to account for variations due to the light source.

[0138] Empirical regularization is used to account for the remaining non-hemoglobinic variation sources. Regularization involves adding a small amount of irrelevant variation to V, equivalent to adding a small constant to the diagonal elements of the covariance matrix, increasing all eigenvalues ​​of V by this constant, thereby preventing any component from becoming too small. It will not have excessively large components, and k will have a smaller norm, corresponding to better robustness to unexpected mutations.

[0139] The polychromatic vector (k) was then calculated using the formula described above. The resulting polychromatic vector k is (-.2104, -.3096, 1.4041, -1.1509, .4806, -.0978, -.1175) and has a norm of 1.9211. The expected interference magnitude was calculated by multiplying k by the main spectrum of each data set. The RMS interference for lipemia and bilirubin was reduced to 0.26% and 1.7%, respectively.

[0140] Experiments showed that using the shortest seven or eight wavelengths described above on the AU 480 (Beckman Coulter, Brea, California) provided good performance. Seven shortest wavelengths ranging from 340 nm to 540 nm were used, along with a regularization of 0.0003. The wavelengths used were 340 nm, 380 nm, 410 nm, 450 nm, 480 nm, 520 nm, and 540 nm.

[0141] Performance was then evaluated using an AU 480 (Beckman Coulter, Brea, California). Hemoglobin judgment values ​​for 66 data sets were calculated using k (referred to herein as “multicolor OD”) as described above, and then compared with hemoglobin judgment values ​​measured at LIH (“AU OD”). Multicolor OD is proportional to hemoglobin concentration. Multicolor OD is calculated by the dot product (also known as the inner product) of the multicolor vector and the measured OD, as shown in the following formula:

[0142]

[0143] The multicolor OD was calculated at measurement point 3 (MP3) (measurement; approximately 40 seconds after sample addition) and measurement point 0 (MP0) (blank; the first measurement point before sample addition), and then the OD was used. MP3 – (90 / 91.2) OD MP0 The final multicolor OD was calculated. The coefficient 90 / 91.2 was derived from correcting for dilution due to sample addition using 90 mL of reagent and 1.2 mL of sample. The AU OD provided by the instrument has been scaled. An OD of 0.266 was found. AU – 0.002 is a perfect match for multicolor OD. Figure 5-7 Multicolor and AU OD are shown respectively using rhombuses and hollow circles; Figure 5 , 6 Figures 7 and 8 show the data for lipids, bilirubin, and hemoglobin, respectively. Figure 5 This demonstrates the quantification of hemoglobin in the presence of lipemia, without the presence of bilirubin and hemoglobin. Figure 6 This demonstrates the quantification of hemoglobin in the presence of bilirubin in the absence of lipemia and hemoglobin. Figure 7 This demonstrates hemoglobin quantification in the presence of hemoglobin without lipemia and bilirubin. Since lipemia and bilirubin samples do not contain hemoglobin, the correct OD is zero. AU OD shows some lipemia interference and strong bilirubin interference. Figure 7 The OD values ​​of the hemoglobin samples are shown. The correlation between the two OD values ​​is very close, with a correlation coefficient of 0.999967.

[0144] Example 2 - Variation in the potassium / hemoglobin ratio in red blood cells among patients

[0145] Whole blood samples were collected from a mixture of 20 male and female donors. Two tubes were collected from each donor. Hemolysate was then prepared from each tube. Each tube was inverted and centrifuged at 3000 rpm for 10 minutes. The supernatant removed from each tube using a Pasteurized pipette was discarded and replaced with 0.9% NaCl, using approximately 60-70% of the red blood cell volume. Each tube was sealed and gently inverted 10 times to resuspend the cells. The tubes were centrifuged at 3000 rpm for 10 minutes, and the supernatant was discarded. The cells in each tube were washed again with 0.9% NaCl. The tubes were resuspended in the packaged cells using approximately half a volume of deionized water (instead of saline solution), or less deionized water if it was suspected that the final hemoglobin concentration in the test chamber after dilution might revert to below the desired concentration (500 mg / dL-1000 mg / dL). Finally, the tubes were frozen for several days.

[0146] The test tubes were then thawed and brought to room temperature. Two test tubes from the same donor were combined to produce 20 separate lysate suspensions. The lysate suspensions were centrifuged at 4,200 rpm for 18 minutes to remove the matrix. Individual supernatants (hemolysate products) were collected separately using a Pasteurized pipette. For each individual supernatant, each precipitate was discarded. Individual hemolysate products were refrozen until the day of testing.

[0147] The tests were performed using a Beckman Coulter AU480. First, hemoglobin levels of three hemolysed products (two copies) were measured using an offline HbA1c assay. The hemoglobin results were 17.75 g / dL, 19.04 g / dL, and 17.60 g / dL, with an average of 18.13 g / dL. Based on this, it was determined that 0.3 mL of hemolysed product should be incorporated into a 5.7 mL serum pool to obtain a hemoglobin level of approximately 900 mg / dL. Donor serum samples were thawed and pooled to create a baseline serum pool. The serum pool was divided into 21 portions—20 portions, each 5.7 mL, for 20 hemolysed products, and a larger portion for baseline measurement. 0.3 mL of one hemolysed product was incorporated into each of the 5.7 mL portions. The larger baseline portion was not incorporated. After running the control, potassium and LIH measurements were as follows: 1) baseline portion, 5 replicas; 2) four replicas for each of the 20 incorporation portions; 3) baseline portion, 5 replicas.

[0148] Use the following equation to determine the hemoglobin value based on the optical density (OD) at measurement point 3:

[0149]

[0150] Where H is the hemoglobin threshold value calculated by AU480 software, and the subscript indicates the wavelength of the OD used. One outlier was identified in the fourth copy of donor sample 9. The outlier result was 4.4547, compared to an average result of 4.3182 for the other three copies. The outlier has been removed from the analysis.

[0151] Although hemoglobin judgment values ​​were affected by bilirubin, jaundice judgment values ​​were very small and consistent across samples. Therefore, bilirubin interference was not expected to affect the analysis. Mean potassium and hemoglobin results were calculated for each donor sample. Baseline potassium and hemoglobin values ​​were subtracted from the corresponding results. Finally, the correction factor was calculated as (K – baseline K) / (H – baseline H), where k and H are the potassium result and hemoglobin judgment value, respectively. The correction factor represents the hemolysis-induced potassium / hemoglobin ratio for each donor, in (mM / L) / (H judgment units). The mean correction factor was 0.769, ranging from 0.680 to 0.821, representing 11.5% lower to 6.7% higher than the mean. The CV was 4.3%. Figure 8 Individual correction factors are shown.

[0152] The uncertainty of the correction factor is a key factor in potassium hemolysis correction. As shown in the following equation, The correction is proportional to H. Similarly, the uncertainty of the correction is also proportional to H. If H is large enough, the uncertainty of the hemolysis correction may be unacceptable. For example, suppose the maximum permissible error for the corrected potassium result is set to E. If the uncertainty of the correction factor c is Δc, then the uncertainty of the corrected result (ignoring the uncertainty of the measured result) is HΔc. produce The requirements specify an upper limit for the amount of hemolysis that can be reasonably corrected. The smaller the value, the higher the upper limit of H.

[0153] When the Beckman Coulter LIH assay (OSR62166) is run on an AU series analyzer, hemolysis results are reported as “N”, “+”, “++”, “+++”, “++++”, or “+++++”. These classifications are intended to be consistent with conventional visual hemolysis classifications and correspond to approximately 0–50 mg / dL, 50–100 mg / dL, 100–200 mg / dL, 200–300 mg / dL, 300–500 mg / dL, and >500 mg / dL hemoglobin, respectively. A conservative total tolerance of 0.2 mmol / L for potassium is provided by the Royal College of Pathologists of Australia (RCPA). The maximum extreme value of c in the study is used. = 0.0883. This gives an upper limit of H of 2.26. This roughly corresponds to 500 mg / dL of hemoglobin, which is very severe hemolysis, corresponding to the AU label on the boundary between ++++ and +++++. AU currently labels potassium at + or higher. In one study, 7.41% of the samples were labeled + or higher. In contrast, only 0.16% of the samples were ++++ or higher, and only 0.03% were +++++.

[0154] The average correction factor can be used to estimate the H level when the difference between the corrected and uncorrected results exceeds the allowable error. This is determined by... This corresponds to approximately 60 mg / dL, slightly above the lower limit of the + label. Therefore, without hemolysis correction, samples labeled + typically have clinically inaccurate results. However, with hemolysis correction, samples labeled +, ++, +++, and most ++++ still yield acceptable accurate results, while +++++ will still be labeled as inaccurate. Thus, even with correction factor uncertainty, hemolysis causes clinically unacceptable interference to hemolysis-corrected results (e.g., 0.16%) much less frequently than uncorrected results (e.g., 7.41%).

[0155] It is also helpful to examine the effect of applying hemolysis correction to the data. Correction is performed using the equation above, where c is set to 0.769, which is the average correction factor. Figure 9 Uncorrected potassium results are displayed as circles, and corrected results are displayed as "x" symbols. The purpose of hemolysis correction is to estimate the potassium results before hemolysis. This is represented by the unadulterated serum pool, indicated by dashed lines.

[0156] The hemolysis level was approximately 900 mg / dL, more severe than expected in a clinical setting. Nevertheless, Table 1 shows that the corrected results were closer to the pre-hemolysis values ​​than the uncorrected results. Of the 80 corrected results, the largest deviation was -0.41 mmol / L (the second copy of Sample 1), and 90% of the results were within ±0.2 mmol / L. The mean deviation was negligible at -0.02 mmol / L. This is highly favorable compared to the performance of the uncorrected results, which had a minimum, mean, and maximum deviation of 2.56 mmol / L, 3.09 mmol / L, and 3.77 mmol / L, respectively.

[0157] Table 1. Performance of uncorrected and corrected potassium results

[0158]

[0159] Finally, it must be noted that some (e.g., approximately 2%) patients have hemolytic disorders. See, for example, Hemolyzed Specimens: Major Challenge for Identifying and Rejecting Specimens in Clinical Laboratories, Oman Med. J., March 2019; 34(2): 94-98. In such cases, clinicians must determine whether the hemolysis is primarily caused by in vitro or in vivo hemolysis, thus applying either corrected or uncorrected results. Therefore, it is recommended to provide both uncorrected and corrected results.

[0160] When used herein, the terms "preferred" and "ideal" refer to embodiments of this disclosure that may provide certain benefits in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are useless, nor is it intended to exclude other embodiments from the scope of this disclosure.

[0161] The terms “comprising,” “including,” “having,” and similar variations thereof, when used in the specification and claims, are not restrictive. Such terms are to be understood as implying inclusion of the stated steps or elements or groups of steps or elements, but not excluding any other steps or elements or groups of steps or elements. In contrast, the term “consisting of” means including and limited to anything following the phrase “consisting of.” Thus, the phrase “consisting of” indicates that the listed elements are necessary or mandatory, and other elements may be absent. “Substantially consisting of” means including any element listed following the phrase, and is limited to other elements that do not interfere with or facilitate the activity or action specified for the listed elements in this disclosure. Thus, the phrase “substantially consisting of” indicates that the listed elements are necessary or mandatory, but other elements are optional and may be present or absent depending on whether they substantially affect the activity or action of the listed elements.

[0162] Unless otherwise stated, “a / an”, “the” and “at least one” are used interchangeably and mean one or more.

[0163] As used herein, unless the content explicitly indicates otherwise, the term "or" is generally used in its usual meaning, including "and / or".

[0164] The term “and / or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0165] As used herein, the use of endpoints to describe a numerical range includes all numbers encompassed within the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Furthermore, specified numbers (e.g., up to 50) mentioned within the disclosure of the phrase "at most" include said numbers (e.g., 50).

[0166] When used in this document, the term “in the range” (and similar phrases) concerning numerical values ​​includes the endpoints of the stated numerical range.

[0167] For any method disclosed herein that includes discrete steps, the steps may be performed in any feasible order, and any combination of two or more steps may be performed simultaneously if appropriate and operationally possible.

[0168] All headings are for the convenience of the reader and, unless otherwise specified, should not be used to limit the meaning of the text following the heading. Furthermore, all patent and non-patent references cited herein are incorporated herein by reference in their entirety.

[0169] Throughout this specification, references to "an embodiment," "an embodiment," "some embodiments," or "a number of embodiments," etc., mean that a particular feature, configuration, composition, or material or property described in connection with the embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of such phrases throughout this specification does not necessarily refer to the same embodiment of this disclosure. Furthermore, in one or more embodiments, particular features, configurations, compositions, or properties may be combined in any suitable manner.

[0170] Unless otherwise stated, all figures used in the specification and claims reflecting the quantity of components, measured values, molecular weights, etc., should be understood to include variations in the measured quantities, which would be expected by a person skilled in the art to perform the measurements with a degree of care commensurate with the purpose of the measurement and the accuracy of the associated measuring equipment. Therefore, unless otherwise indicated, the numerical parameters set forth in the specification and claims are approximations that can vary depending on the desired properties sought through this disclosure. At a minimum, each numerical parameter should be interpreted based on the number of significant figures reported and by applying conventional rounding techniques. In some cases, the term "about" may be used before numerical representations, such as pH, temperature, amount, or concentration, indicating approximations that can vary based on quantities that have no significant effect on the resulting structure, stability, activity, or outcome.

[0171] Although the numerical ranges and parameters described in this disclosure are approximate, the values ​​illustrated in the specific examples are reported as precisely as possible. Those skilled in the art will understand that all values ​​inherently contain ranges that necessarily derive from the standard deviations found in their respective test measurements.

[0172] While certain embodiments have been described in this disclosure, various changes and equivalents may be made without departing from the scope of the invention. Furthermore, many modifications may be made to adapt particular situations or materials to the teachings of this disclosure without departing from the scope of the appended claims. Therefore, this disclosure is not limited to the specific embodiments disclosed, but includes all embodiments falling within the scope of the appended claims.

[0173] In at least one aspect, this disclosure provides a method for analyzing a blood sample to determine a potassium concentration corrected for interference, the method comprising at least the steps of: analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a corrected potassium concentration corrected for interference. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0174] In at least one aspect, this disclosure provides a method for analyzing a blood sample to determine a potassium concentration corrected for interference, the method comprising: analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interference indicator in the blood sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0175] In at least one aspect, this disclosure provides a method for determining potassium imbalance, the method comprising: analyzing a blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a corrected potassium concentration corrected for interference. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0176] In at least one aspect, this disclosure provides a method for determining potassium imbalance, the method comprising: analyzing a blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for the interference. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0177] In at least one aspect, this disclosure provides a method for analyzing a blood sample including an interference indicator to determine a potassium concentration corrected for interference, the method comprising: analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration in the blood sample that is not corrected for interference; receiving data at a processor corresponding to the uncorrected potassium concentration; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of the interference indicator; and receiving data at the processor corresponding to the concentration of the interference indicator; and determining, by the processor, a corrected potassium concentration corrected for interference, wherein the corrected potassium concentration is determined by applying data from the second assay to data from the first assay. In some embodiments, wherein the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0178] In at least one aspect, this disclosure provides a method for analyzing a blood sample including an interference indicator to determine a potassium concentration corrected for interference, the method comprising: analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; receiving data corresponding to the initial potassium concentration at a processor; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of the interference indicator in the blood sample; and receiving data corresponding to the concentration of the interference indicator at the processor; and determining a final potassium concentration corrected for interference by the processor, wherein the final potassium concentration is determined by applying data from the second assay to data from the first assay. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0179] In at least one aspect, this disclosure provides a method for improving the determination of potassium concentration in a biological sample, the method comprising: analyzing the biological sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the biological sample with a second assay, wherein the second assay determines a concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a potassium concentration, wherein the corrected potassium concentration is corrected for interference. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0180] In at least one aspect, this disclosure provides a method for improving the determination of potassium concentration in a biological sample, the method comprising: analyzing the biological sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the biological sample; analyzing the biological sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the biological sample; and applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0181] In at least one aspect, this disclosure provides a method for indicating whether a patient has an electrolyte imbalance, the method comprising: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected electrolyte concentration. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the method further includes, after reporting the corrected electrolyte concentration, indicating whether the corrected electrolyte concentration is above or below an electrolyte imbalance threshold.In some embodiments, the report further includes reporting the uncorrected electrolyte concentration. In some embodiments, the report includes reporting a comparison between the uncorrected electrolyte concentration and the corrected electrolyte concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration.

[0182] In at least one aspect, this disclosure provides a method for indicating whether a patient has an electrolyte imbalance, the method comprising: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial electrolyte concentration in the biological sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the biological sample; applying data from the second assay to data from the first assay to determine a final electrolyte concentration corrected for interference; and reporting the final electrolyte concentration. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantification further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the method further comprises using the ISE assay to quantify the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the method further includes, after reporting the corrected electrolyte concentration, indicating whether the corrected electrolyte concentration is above or below an electrolyte imbalance threshold. In some embodiments, the reporting further includes reporting the uncorrected electrolyte concentration.In some embodiments, the report includes reporting a comparison between the uncorrected electrolyte concentration and the corrected electrolyte concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration.

[0183] In at least one aspect, this disclosure provides a method for determining potassium concentration in a blood sample, an improvement comprising determining a corrected potassium concentration by attenuating interference. In some embodiments, the improvement further comprises applying the concentration of an interference indicator to an uncorrected potassium concentration that is not corrected for interference to remove interference. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the improvement further comprises using an ion-selective electrode (ISE) assay to determine the uncorrected potassium concentration. In some embodiments, the improvement further comprises using a lipemia, jaundice, and hemolysis (LIH) assay to determine the hemoglobin concentration. In some embodiments, the method further comprises using the LIH assay to quantitatively determine the hemoglobin concentration, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, the application comprises applying a correction factor to determine a corrected potassium concentration. In some embodiments, the application includes the steps of: multiplying the concentration of the interference indicator by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration.

[0184] In at least one aspect, this disclosure provides a method for correcting for interference in an assay, the method comprising: analyzing a sample with a first assay, wherein the first assay determines an uncorrected concentration of a target analyte that is not corrected for interference; analyzing the sample with a second assay, wherein the second assay determines a concentration of an interference indicator; and applying data from the second assay to data from the first assay to determine a corrected concentration of the target analyte that is corrected for interference. In some embodiments, the target analyte is one or more electrolytes. In some embodiments, the target analyte is potassium. In some embodiments, the target analyte is an enzyme. In some embodiments, the target analyte is lactate dehydrogenase (LDH). In some embodiments, the interference indicator is hemoglobin. In some embodiments, the concentration of hemoglobin is determined using a lipemia, jaundice, and hemolysis (LIH) assay.

[0185] In at least one aspect, this disclosure provides a method for correcting for interference in an assay, the method comprising: analyzing a sample with a first assay, wherein the first assay is performed to determine an initial target analyte concentration in the sample; analyzing the sample with a second assay, wherein the second assay is performed to determine a concentration of an interference indicator in the sample; and applying data from the second assay to data from the first assay to determine a final target analyte concentration corrected for interference. In some embodiments, the target analyte is one or more electrolytes. In some embodiments, the target analyte is potassium. In some embodiments, the target analyte is an enzyme. In some embodiments, the target analyte is lactate dehydrogenase (LDH). In some embodiments, the interference indicator is hemoglobin. In some embodiments, the concentration of hemoglobin is determined using a lipemia, jaundice, and hemolysis (LIH) assay.

[0186] In at least one aspect, this disclosure provides a method for treating a patient suspected of having an electrolyte imbalance, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes. In some embodiments, the method further comprises, after reporting the corrected concentration of the one or more electrolytes, determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's electrolyte imbalance with the treatment plan. In some embodiments, the one or more electrolytes comprise potassium. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variation source includes instrument-induced variation. In some embodiments, applying the data includes applying a correction factor to determine the corrected electrolyte concentration. In some embodiments, the report further includes reporting the uncorrected electrolyte concentration.In some embodiments, the report includes a report of the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected electrolyte concentration and the corrected electrolyte concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected electrolyte concentration to determine the corrected electrolyte concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof. In some embodiments, the utilized treatment plan is used to treat hyperkalemia. In some embodiments, the utilized treatment plan is used to treat hypokalemia masked by interference.

[0187] In at least one aspect, this disclosure provides a method for treating a patient suspected of having an electrolyte imbalance, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial concentration of one or more electrolytes; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final concentration of the one or more electrolytes corrected for interference; and reporting the final concentration of the one or more electrolytes. In some embodiments, the method further comprises, after reporting the corrected concentration of the one or more electrolytes, determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's electrolyte imbalance with the treatment plan. In some embodiments, the one or more electrolytes comprise potassium. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variation source includes instrument-induced variation. In some embodiments, applying the data includes applying a correction factor to determine the corrected electrolyte concentration. In some embodiments, the report further includes reporting the uncorrected electrolyte concentration.In some embodiments, the report includes a report of the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected electrolyte concentration and the corrected electrolyte concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected electrolyte concentration to determine the corrected electrolyte concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof. In some embodiments, the utilized treatment plan is used to treat hyperkalemia. In some embodiments, the utilized treatment plan is used to treat hypokalemia masked by interference.

[0188] In at least one aspect, this disclosure provides a method for treating a patient suspected of having an electrolyte imbalance, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of one or more electrolytes that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration with the reporting threshold; and if the difference in the corrected electrolyte concentration is greater than the reporting threshold, reporting both the corrected electrolyte concentration and the uncorrected electrolyte concentration. In some embodiments, the method further comprises, after reporting the concentration of the one or more electrolytes, determining whether the patient has a hemolytic disease and determining a treatment plan for the patient. In some embodiments, the method further includes treating the patient's electrolyte imbalance with the treatment plan after determining the treatment plan for the patient. In some embodiments, the one or more electrolytes comprise potassium. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further includes quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination includes measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin.In some embodiments, generating the covariance matrix includes adding irrelevant variation to the covariance matrix. In some embodiments, the non-hemoglobinic variation sources include instrument-induced variation. In some embodiments, the method further includes using the ISE assay to quantitatively determine the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected electrolyte concentration to determine the corrected electrolyte concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0189] In at least one aspect, this disclosure provides a method for treating a patient suspected of having an electrolyte imbalance, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial concentration of one or more electrolytes in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final concentration of the one or more electrolytes, wherein the corrected electrolyte concentration is corrected for interference; and reporting the corrected concentration of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the final electrolyte concentration and the initial electrolyte concentration with the reporting threshold; and if the difference in the final electrolyte concentration is greater than the reporting threshold, reporting both the final electrolyte concentration and the initial electrolyte concentration. In some embodiments, the method further comprises, after reporting the concentration of the one or more electrolytes, determining whether the patient has a hemolytic disease and determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's electrolyte imbalance with the treatment plan. In some embodiments, the one or more electrolytes comprise potassium. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin.In some embodiments, generating the covariance matrix includes adding irrelevant variation to the covariance matrix. In some embodiments, the non-hemoglobinic variation sources include instrument-induced variation. In some embodiments, the method further includes using the ISE assay to quantitatively determine the uncorrected potassium concentration. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected electrolyte concentration to determine the corrected electrolyte concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0190] In at least one aspect, this disclosure provides a method for treating a patient suspected of having hyperkalemia, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the first assay to data from the second assay to determine a corrected potassium concentration, wherein the corrected potassium concentration is corrected for interference; and reporting the corrected potassium concentration. In some embodiments, the method further comprises, after reporting the corrected potassium concentration, determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's hyperkalemia with the treatment plan. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipidemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining a multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide a multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variation source includes instrument-induced variation. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes reporting the uncorrected potassium concentration. In some embodiments, the report includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration.In some embodiments, applying the data includes the steps of: multiplying the concentration of the interference indicator by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, reporting both the corrected potassium concentration and the uncorrected potassium concentration.

[0191] In at least one aspect, this disclosure provides a method for treating a patient suspected of having hyperkalemia, wherein the patient does not have a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference; and reporting the final potassium concentration. In some embodiments, the method further comprises determining a treatment plan for the patient after reporting the corrected potassium concentration. In some embodiments, the method further comprises treating the patient's hyperkalemia with the treatment plan after determining the treatment plan for the patient. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, applying the data comprises applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes a report of the uncorrected potassium concentration. In some embodiments, the report includes a report of the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration.In some embodiments, applying the data includes the steps of: multiplying the concentration of the interference indicator by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, reporting both the corrected potassium concentration and the uncorrected potassium concentration.

[0192] In at least one aspect, this disclosure provides a method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient does not have a hemolytic condition, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected potassium concentration not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected potassium concentration, wherein the corrected potassium concentration is corrected for interference; and reporting the corrected potassium concentration. In some embodiments, the method further comprises, after reporting the corrected potassium concentration, determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining a treatment plan for the patient, treating the patient for hyperkalemia with the treatment plan. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining a multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide a multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variation source includes instrument-induced variation. In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes reporting the uncorrected potassium concentration. In some embodiments, the report includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration.In some embodiments, applying the data includes the steps of: multiplying the concentration of the interference indicator by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, reporting both the corrected potassium concentration and the uncorrected potassium concentration.

[0193] In at least one aspect, this disclosure provides a method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient does not have a hemolytic condition, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration in the blood sample; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interference indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration corrected for interference; and reporting the final potassium concentration. In some embodiments, the method further comprises determining a treatment plan for the patient after reporting the corrected potassium concentration. In some embodiments, the method further comprises treating the patient for hyperkalemia with the treatment plan after determining the treatment plan for the patient. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants. In some embodiments, applying the data comprises applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes a report of the uncorrected potassium concentration. In some embodiments, the report includes a report of the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration.In some embodiments, applying the data includes the steps of: multiplying the concentration of the interference indicator by a correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the method further includes the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, reporting both the corrected potassium concentration and the uncorrected potassium concentration.

[0194] In at least one aspect, this disclosure provides a method for treating a patient suspected of having hyperkalemia, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of potassium that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of potassium, wherein the corrected potassium concentration is corrected for interference; and reporting an electrolyte dataset, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, reporting both the corrected potassium concentration and the uncorrected potassium concentration. In some embodiments, the method further comprises, after reporting the electrolyte concentration, determining whether the patient has a hemolytic disease and determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's interference-masked hypokalemia with the treatment plan. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants.In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes reporting the uncorrected potassium concentration. In some embodiments, the report includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0195] In at least one aspect, this disclosure provides a method for treating a patient suspected of having hyperkalemia, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration, wherein the final potassium concentration is corrected for interference; and reporting the corrected concentrations of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the final electrolyte concentration and the initial electrolyte concentration with the reporting threshold; and if the difference in the final electrolyte concentration is greater than the reporting threshold, reporting both the final electrolyte concentration and the initial electrolyte concentration. In some embodiments, the method further comprises, after reporting the electrolyte concentrations, determining whether the patient has a hemolytic disease and determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's interference-masked hypokalemia with the treatment plan. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining a multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide a multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variation sources include lipemia and bilirubin. In some embodiments, generating the covariance matrix involves adding irrelevant variations to the covariance matrix. In some embodiments, the non-hemoglobin variation sources include instrument-induced variations.In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes reporting the uncorrected potassium concentration. In some embodiments, the report includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0196] In at least one aspect, this disclosure provides a method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay determines an uncorrected concentration of potassium that is not corrected for interference; analyzing the blood sample with a second assay, wherein the second assay determines a concentration of an interference indicator; applying data from the second assay to data from the first assay to determine a corrected concentration of potassium, wherein the corrected potassium concentration is corrected for interference; and reporting an electrolyte dataset, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the corrected potassium concentration and the uncorrected potassium concentration with the reporting threshold; and if the difference in the corrected potassium concentration is greater than the reporting threshold, reporting both the corrected potassium concentration and the uncorrected potassium concentration. In some embodiments, the method further comprises, after reporting the electrolyte concentration, determining whether the patient has a hemolytic disease and determining a treatment plan for the patient. In some embodiments, the method further includes treating the patient's interference-masked hypokalemia with the treatment plan after determining a treatment plan for the patient. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further includes quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination includes measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants.In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes reporting the uncorrected potassium concentration. In some embodiments, the report includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0197] In at least one aspect, this disclosure provides a method for treating a patient suspected of having interference-masked hypokalemia, wherein the patient is suspected of having a hemolytic disease, the method comprising the steps of: collecting at least one blood sample from the patient; analyzing the blood sample with a first assay, wherein the first assay is performed to determine an initial potassium concentration; analyzing the blood sample with a second assay, wherein the second assay is performed to determine a concentration of an interfering indicator in the blood sample; applying data from the second assay to data from the first assay to determine a final potassium concentration, wherein the final potassium concentration is corrected for interference; and reporting the corrected concentrations of the one or more electrolytes, wherein the reporting comprises the steps of: establishing a reporting threshold; comparing the difference between the final electrolyte concentration and the initial electrolyte concentration with the reporting threshold; and if the difference in the final electrolyte concentration is greater than the reporting threshold, reporting both the final electrolyte concentration and the initial electrolyte concentration. In some embodiments, the method further comprises, after reporting the electrolyte concentration, determining whether the patient has a hemolytic disease and determining a treatment plan for the patient. In some embodiments, the method further comprises, after determining the treatment plan for the patient, treating the patient's interference-masked hypokalemia with the treatment plan. In some embodiments, the interference indicator is hemoglobin. In some embodiments, the first assay is an ion-selective electrode (ISE) assay. In some embodiments, the second assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density (OD) at two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants.In some embodiments, applying the data includes applying a correction factor to determine a corrected potassium concentration. In some embodiments, the report further includes reporting the uncorrected potassium concentration. In some embodiments, the report includes reporting the uncorrected electrolyte concentration and a note, wherein the note reports the difference between the uncorrected potassium concentration and the corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

[0198] In at least one aspect, this disclosure provides a method for determining the necessity of a second blood draw, wherein the method comprises: collecting a first blood sample using a first blood draw; analyzing the first blood sample using a assay to determine a concentration of hemoglobin; establishing a re-draw threshold; comparing the concentration of hemoglobin with the re-draw threshold; and if the concentration of hemoglobin is greater than the re-draw threshold, collecting a second blood sample using a second blood draw. In some embodiments, establishing the re-draw threshold further comprises the steps of: (i) establishing a correction factor uncertainty; (ii) establishing a measurement target error threshold; and (iii) calculating the re-draw threshold based on the correction factor uncertainty and the measurement target error threshold. In some embodiments, the assay is a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the method further comprises quantitatively determining the concentration of hemoglobin using the LIH assay, wherein the quantitative determination comprises measuring optical density at at least two or more wavelengths. In some embodiments, the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix comprises adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variants include instrument-induced variants.

[0199] In at least one aspect, this disclosure provides a clinical chemistry instrument comprising: a first assay system configured to determine an uncorrected potassium concentration not corrected for interference, the first assay system including a first sensor; and a second assay system configured to determine the concentration of an interfering indicator, the second assay system including a second sensor; and a processor configured to receive data from the first sensor and the second sensor and determine a corrected potassium concentration corrected for interference. In some embodiments, the corrected potassium concentration is corrected for interference without requiring further assay processing beyond the clinical chemistry instrument itself. In some embodiments, the interfering indicator is hemoglobin. In some embodiments, the first assay system is configured to perform an ion-selective electrode (ISE) assay. In some embodiments, the second assay system is configured to perform a lipemia, jaundice, and hemolysis (LIH) assay. In some embodiments, the second assay system is configured to quantitatively determine the concentration of the interfering indicator, wherein the quantitative determination includes measuring optical density at two or more wavelengths using the first instrument. In some embodiments, the processor is configured to apply the data received from the second sensor to the data received from the first sensor to determine the corrected potassium concentration. In some embodiments, the processor is configured to apply the data received from the second sensor to the data received from the first sensor to determine the final potassium concentration. In some embodiments, the quantitative determination further includes determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD includes the steps of: (i) generating an extinction coefficient vector characterizing the OD spectrum of hemoglobin at two or more wavelengths; (ii) generating a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) generating a multicolor vector that is a function of the extinction coefficient vector and the covariance matrix, wherein the multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and wherein the multicolor OD is proportional to the hemoglobin concentration. In some embodiments, the non-hemoglobin variants include lipemia and bilirubin. In some embodiments, generating the covariance matrix includes adding irrelevant variants to the covariance matrix. In some embodiments, the non-hemoglobin variation source includes instrument-induced variation. In some embodiments, applying the data includes applying a correction factor.In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the uncorrected potassium concentration to determine the corrected potassium concentration. In some embodiments, applying the data includes the steps of: multiplying the interference indicator concentration by the correction factor to determine the interference magnitude; and subtracting the interference magnitude from the initial potassium concentration to determine the final potassium concentration.

Claims

1. A method for determining potassium concentration in a blood sample, the improvement comprising determining a corrected potassium concentration by attenuating interference.

2. The method of claim 1, wherein the improvement further comprises applying the concentration of the interference indicator to an uncorrected potassium concentration that has not been corrected for the interference to remove the interference.

3. The method according to claim 2, wherein the interference indicator is hemoglobin.

4. The method according to any one of claims 2 to 3, wherein the improvement further comprises using an ion-selective electrode (ISE) to determine the uncorrected potassium concentration.

5. The method according to any one of claims 3 to 4, wherein the improvement further comprises using lipemia, jaundice, and hemolysis (LIH) assays to determine hemoglobin concentration.

6. The method of claim 5, wherein the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths.

7. The method of claim 6, wherein the quantitative determination further comprises determining the multicolor optical density (OD) of the biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the following steps: (i) Generate an extinction coefficient vector, which characterizes the OD spectrum of hemoglobin at two or more wavelengths; (ii) Generate a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) Generate a polycolor vector, which is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and the multicolor OD is proportional to the hemoglobin concentration.

8. The method of claim 7, wherein the non-hemoglobin variant source comprises lipemia and bilirubin.

9. The method according to any one of claims 7 to 8, wherein generating the covariance matrix comprises adding uncorrelated variations to the covariance matrix.

10. The method according to any one of claims 7 to 9, wherein the non-hemoglobin variant source includes variants induced by the instrument.

11. The method according to any one of claims 2 to 10, wherein the application comprises applying a correction factor to determine a corrected potassium concentration.

12. The method of claim 11, wherein the application comprises the following steps: Multiply the concentration of the interference indicator by the correction factor to determine the interference magnitude; and The corrected potassium concentration is determined by subtracting the disturbance magnitude from the uncorrected potassium concentration.

13. A method for treating a patient suspected of having electrolyte imbalance, wherein the patient does not have hemolytic disease, the method comprising the steps of: Collect at least one blood sample from the patient; The blood sample is analyzed using a first assay, wherein the first assay is performed to determine the initial concentration of one or more electrolytes; The blood sample is analyzed using a second assay, wherein the second assay is performed to determine the concentration of interfering indicators in the blood sample; The data from the second measurement is applied to the data from the first measurement to determine the final concentration of the one or more electrolytes corrected for interference; Report the final concentration of the one or more electrolytes.

14. The method of claim 13, wherein the method further comprises determining a treatment plan for the patient after reporting the corrected concentrations of the one or more electrolytes.

15. The method of claim 14, wherein the method further comprises, after determining the treatment plan for the patient, treating the patient's electrolyte imbalance with the treatment plan.

16. The method according to any one of claims 13 to 15, wherein the one or more electrolytes comprise potassium.

17. The method according to any one of claims 13 to 16, wherein the interference indicator is hemoglobin.

18. The method according to any one of claims 13 to 17, wherein the first determination is an ion-selective electrode (ISE) determination.

19. The method according to any one of claims 13 to 18, wherein the second assay is a lipidemia, jaundice, and hemolysis (LIH) assay.

20. The method of claim 19, wherein the method further comprises quantitatively determining the hemoglobin concentration using the LIH assay, wherein the quantitative determination comprises measuring optical density at two or more wavelengths.

21. The method of claim 20, wherein the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the following steps: (i) Generate an extinction coefficient vector, which characterizes the OD spectrum of hemoglobin at two or more wavelengths; (ii) Generate a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) Generate a polycolor vector, which is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and the multicolor OD is proportional to the hemoglobin concentration.

22. The method of claim 21, wherein the non-hemoglobin variant source comprises lipemia and bilirubin.

23. The method of any one of claims 21 to 22, wherein generating the covariance matrix comprises adding uncorrelated variations to the covariance matrix.

24. The method according to any one of claims 21 to 23, wherein the non-hemoglobin variant source includes variants induced by the instrument.

25. The method of any one of claims 13 to 24, wherein applying the data comprises applying a correction factor to determine the final concentration of the one or more electrolytes.

26. The method of claims 13 to 25, wherein the report further comprises reporting the initial concentration of the one or more electrolytes.

27. The method of claim 26, wherein the report comprises reporting the initial electrolyte concentration and a note, wherein the note reports the difference between the uncorrected electrolyte concentration and the final concentration of the one or more electrolytes.

28. The method of claim 25, wherein applying the data comprises the following steps: Multiply the concentration of the interference indicator by the correction factor to determine the interference magnitude; and The final concentration of the one or more electrolytes is determined by subtracting the disturbance magnitude from the initial concentration of the one or more electrolytes.

29. The method according to any one of claims 13 to 28, wherein the method further comprises the following steps: Establish reporting thresholds; The difference between the corrected electrolyte concentration and the uncorrected electrolyte concentration is compared with the reporting threshold; and If the difference between the final electrolyte concentrations is greater than the reporting threshold, then both the final electrolyte concentration and the uncorrected electrolyte concentration are reported.

30. The method according to any one of claims 14 to 29, wherein the treatment plan utilizes at least one or more of the following: diuretics, blood pressure medications, potassium binders, insulin, sympathomimetic drugs, or calcium gluconate or combinations thereof.

31. The method according to any one of claims 15 to 30, wherein the treatment plan used is for treating hyperkalemia.

32. The method according to any one of claims 15 to 31, wherein the treatment plan used is for treating hypokalemia masked by interference.

33. A clinical chemistry instrument comprising: A first measuring system, configured to determine an initial potassium concentration, the first measuring system comprising a first sensor; as well as A second measurement system, used to determine the concentration of an interfering indicator, includes a second sensor; as well as A processor configured to receive data from the first and second sensors and determine a final potassium concentration corrected for interference.

34. The clinical chemistry instrument of claim 33, wherein the final potassium concentration is corrected for interference without requiring further measurement or processing beyond the clinical chemistry instrument itself.

35. The clinical chemistry instrument according to any one of claims 33 to 34, wherein the interfering indicator is hemoglobin.

36. The clinical chemistry instrument according to any one of claims 33 to 35, wherein the first assay system is configured to perform ion-selective electrode (ISE) assays.

37. The clinical chemistry instrument according to any one of claims 33 to 35, wherein the second assay system is configured to perform lipemia, jaundice, and hemolysis (LIH) assays.

38. The clinical chemistry instrument of claim 37, wherein the second assay system is configured to quantitatively determine the concentration of the interfering indicator, wherein the quantitative determination comprises measuring optical density at two or more wavelengths using the first assay system.

39. The clinical chemistry instrument according to any one of claims 33 to 38, wherein the processor is configured to apply the data received from the second sensor to the data received from the first sensor to determine the final potassium concentration.

40. The clinical chemistry instrument according to any one of claims 33 to 39, wherein the quantitative determination further comprises determining the multicolor optical density (OD) of a biological sample, the multicolor OD minimizing the effects of non-hemoglobin variants, wherein determining the multicolor OD comprises the following steps: (i) Generate an extinction coefficient vector, which characterizes the OD spectrum of hemoglobin at two or more wavelengths; (ii) Generate a covariance matrix associated with non-hemoglobin variants in the OD measured at the two or more wavelengths; and (iii) Generate a polycolor vector, which is a function of the extinction coefficient vector and the covariance matrix. The multicolor vector is applied to the optical density (OD) measured at the two or more wavelengths to provide the multicolor OD, and the multicolor OD is proportional to the hemoglobin concentration.

41. The clinical chemistry instrument of claim 40, wherein the non-hemoglobin variant source comprises lipemia and bilirubin.

42. The clinical chemistry instrument according to any one of claims 40 to 41, wherein generating the covariance matrix comprises adding uncorrelated variations to the covariance matrix.

43. The clinical chemistry instrument according to any one of claims 40 to 42, wherein the non-hemoglobin variant source includes variants induced by the instrument.

44. The clinical chemistry instrument according to any one of claims 38 to 44, wherein the data used in the application includes an application correction factor.

45. The clinical chemistry instrument of claim 44, wherein using the data comprises the following steps: Multiply the concentration of the interference indicator by the correction factor to determine the interference magnitude; and The corrected potassium concentration is determined by subtracting the disturbance magnitude from the uncorrected potassium concentration.

46. ​​The clinical chemistry instrument of claim 39, wherein using the data comprises the following steps: Multiply the concentration of the interference indicator by the correction factor to determine the interference magnitude; and The final potassium concentration is determined by subtracting the disturbance magnitude from the initial potassium concentration.

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