Apparatus and method for performing complete blood counts and determining sedimentation rate

Abstract

An apparatus for performing a complete blood count and determining a sedimentation rate, comprising a first group (4) arranged to sample a blood sample from a tube and perform a complete blood count on said sample, and a second group (6) arranged to sample a blood sample from the tube and perform a sedimentation rate determination, the apparatus comprising at least one sampling member (8) which can be controlled for measurements by the first group (4) and by the second group (6) to sample a blood sample such that a sample sampled for the first group (4) is not used by the second group (6) and a sample sampled for the second group (6) is not used by the first group (4), the second group (6) being provided with a sensor (20) having an infrared light source (12) and an optical sensor (14) arranged substantially opposite each other around a tube (16) connected to an output end of the at least one sampling member (8), such that light emitted by the infrared light source (12) reaches the optical sensor (14) after traversing the tube (16). The apparatus further comprises a converter (10) arranged to receive one or more light transmission measurements from the optical sensor (14) and determine a sedimentation velocity.

Description

[Technical Field]

[0001] The present invention relates to the field of hematology, and more particularly to the measurement of sedimentation rate (hereinafter also called ESR, in English "erythrocyte sedimentation rate" or "ESR"). [Background technology]

[0002] The sedimentation rate is a routine part of a complete blood count (CBC) and can detect the presence of inflammatory or infectious conditions, such as rheumatism, cancer, and other diseases that cause changes in blood protein concentrations. A high ESR indicates an inflammatory state, regardless of its nature. However, a low ESR may remain during the presence of an inflammatory syndrome. Therefore, a high ESR generally indicates the presence of a pathological condition. Combining this nonspecific test with complementary tests allows for a more accurate diagnosis.

[0003] The standard method for measuring ESR is the Westergren method. A thin tube with standardized dimensions is filled with a blood sample, sampled with an anticoagulant, e.g., EDTA, and diluted with sodium citrate, and placed vertically. The ESR measurement is the height (in millimeters) of the plasma column after one hour of sedimentation. For example, for an adult male, a height of less than 10 mm after the first hour of sedimentation is considered normal. The limits of normality are not absolute and vary depending on the patient's age and gender.

[0004] ESR is the result of three steps: aggregation, sedimentation, and roll sedimentation of blood cells.

[0005] The phenomenon of red blood cell aggregation is caused by proteins in blood, and the higher their concentration, the greater the force they exert. The formation of aggregates means that red blood cells "roll" together and form three-dimensional structures. The sedimentation rate depends on the size of the aggregates and the viscosity of the plasma.

[0006] In the final step, the aggregates settle, i.e., they gradually fall to the bottom of the tube and are then compressed, separating the sample into a clear, translucent portion at the top (plasma) and a much darker portion at the bottom (red blood cells). The ESR is measured by the height of the translucent portion.

[0007] The most important inflammatory parameter is aggregation, which is directly dependent on plasma protein concentration. This is what the present invention measures to return ESR values. Although this is a nonspecific parameter, it suppresses interference arising from the last two steps of ESR. There are no standardized parameters that can express the rate or kinetics of aggregation. Therefore, it is important to translate aggregation measurements into ESR.

[0008] Due to the volume of blood (1.6 ml) and the time required to complete (1 hour), the Westergren method is not compatible with hematology equipment for CBC analysis. To overcome these problems, research has been conducted using extinction optical measurements (absorption and scattering) to determine sedimentation velocity, such as in patent US 6,632,679.

[0009] Some patents have proposed incorporating improved ESR measurements into hematology testing devices, such as that described in EP 2921862, in which a volume of blood is drawn and separated into two parts for count (CBC) and sedimentation rate measurement, respectively.

[0010] Therefore, this device is disadvantageous because it links counting measurement with sedimentation velocity measurement and requires a complex device to dispense two blood sample portions via one sample, one to the counting portion on one side and one to the sedimentation velocity measurement portion on the other side, and further because the CBC and ESR measurement operations do not have similar requirements in sample preparation.

[0011] Document ITUA20163693A1 describes a device that makes it possible to carry out hematological analyses on blood samples and to integrate the detection of the blood sedimentation rate (ESR) with the detection of other chemical and physical parameters of the blood.

[0012] Document WO2021 / 097610A1 describes a sample analyzer including a module for measuring erythrocyte sedimentation rate, a module for measuring a hemogram, and a sample allocation module. The sample allocation module is used to collect blood samples and allocate a first portion of the blood sample to the erythrocyte sedimentation rate measurement module and a second portion of the blood sample to the complete blood cell count measurement module. The erythrocyte sedimentation rate measurement module has a measurement tube and an optical measurement device.

[0013] There is no known device that can rapidly perform complete blood count and sedimentation rate determination while being separated from each other and with a simple structure. Summary of the Invention

[0014] The present invention improves this situation. To this end, an apparatus for performing complete blood counts and determining sedimentation rates is provided, which includes a first group configured to sample a blood sample from a tube and perform a complete blood count on the sample, and a second group configured to sample a blood sample from the tube and perform a sedimentation rate determination. The apparatus includes at least one sampling member that can be controlled for measurements by the first group and measurements by the second group so that the sample sampled for the first group is not used by the second group, and the sample sampled for the second group is not used by the first group. The second group includes a sensor having an infrared light source and an optical sensor arranged substantially opposite each other around a tube connected to the output end of the at least one sampling member, such that light emitted by the infrared light source reaches the optical sensor after traversing the tube. The second group is further configured to perform rinsing of the sampling member and the tube between two sedimentation rate measurements, and the optical sensor is configured to perform a blank measurement after the rinsing operation. The apparatus further comprises a converter arranged to receive the blank measurement and one or more light transmission measurements from the optical sensor and to determine the sedimentation velocity from a ratio of the blank measurement and the light transmission measurement.

[0015] This device is particularly advantageous because it can perform sedimentation velocity measurements independently of a complete blood count. In this way, sedimentation velocity measurements remain a less systematic test, but do not interfere with the structure of the device in a way that is likely to affect other functions.

[0016] According to various embodiments, the invention may have one or more of the following features. The infrared light source and the optical sensor are positioned at a distance of less than 10 cm from the sampling end of the sampling member. The second group is arranged upstream of the first group at the inlet of the device or downstream of the first group at the outlet of the device for carrying out complementary measurements of the spraying or staining type. The converter is positioned to determine the time of the lowest light transmittance measurement and the time of the final light transmittance measurement. The optical sensor is positioned to perform a maximum gain between the time of the lowest light transmittance measurement and the time of the final light transmittance measurement, and a minimum gain at other times. The converter is arranged to calculate the sedimentation velocity based on the ratio between the empty measurement and the measurement at the time of the final light transmittance measurement on the one hand, and the ratio between the empty measurement and the measurement at the time of the lowest light transmittance measurement on the other hand. The optical sensor is controlled at a low gain before the blood passes through the substantially transparent portion and at a high gain after the blood passes through the substantially transparent portion. The sampling member is a needle that can be controlled for sampling a blood sample, to which a tube formed with a substantially transparent portion is connected.

[0017] The present invention also relates to a method for performing a complete blood count and determining the sedimentation rate, using a device according to the present invention, which comprises sampling two different samples, on the one hand performing a complete blood count and on the other hand determining the sedimentation rate.

[0018] Other characteristics and advantages of the invention will appear better from a reading of the following description with reference to embodiments given for illustrative and non-limiting purposes and with reference to the drawings, in which: [Brief explanation of the drawings]

[0019] [Figure 1] Overall schematic diagram of the device according to the present invention [Figure 2] Figure 1: Detail of the creation of the elements [Figure 3] Measurement diagram of the device in Figure 1 [Figure 4] Schematic diagram of a first embodiment of the device of FIG. [Figure 5] Schematic diagram of a second embodiment of the device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0020] The drawings and description below contain elements of an essentially constant nature, which therefore serve not only to better understand the invention but may also, where appropriate, contribute to its definition.

[0021] 1 is a general schematic diagram of an apparatus 2 for performing a complete blood count and determining sedimentation velocity measurements according to the present invention. The apparatus 2 comprises a first group 4, a second group 6, a sampling member 8 and a converter 10.

[0022] The first group 4 is arranged to sample the blood sample in the tube and primarily perform a complete blood count on this sample. This measurement can be performed using conventional methods and is known elsewhere. There are many blood testing devices that specialize in this measurement. Blood analyses other than CBC, such as glycated hemoglobin (HbA1c) measurement and C-reactive protein (CRP), can also be performed within group 4.

[0023] The second group 6 is arranged to determine the ESR measurement, and it is to this second group that the present invention is primarily directed. Indeed, as mentioned at the beginning, this test, whether carried out according to the conventional method or by measuring the change in absorbance, is either tedious or, being coupled to a CBC measurement, slows down the operation of the entire device.

[0024] Implementation of the second group 6 according to the present invention allows for the extrapolation of sedimentation velocity measurements by varying absorbance in a manner that is decoupled from CBC or other blood measurements. To this end, the second group 6 is arranged to control the sampling member 8, here a needle, independently of the first group 4, i.e., the sample sampled by the first group 4 is used only for CBC or other blood measurements, and the sample sampled by the second group 6 is used only for ESR measurements.

[0025] Thus, as shown in Figure 1, the first group 4 or the second group 6 controls the needle 8 to sample a blood sample in a blood tube 11. This sample is then brought to the first group 4 for a blood measurement, such as a CBC measurement, or to the second group 6 for a measurement of the change in absorbance. In the latter case, the measurement is sent to the converter 10, which returns an ESR signal and / or an ESR measurement.

[0026] 2 shows an embodiment of the second measuring group 6. According to this embodiment, the second measuring group 6 is formed by a light source 12 and an optical sensor 14 assembled opposite each other around a tube 16 intended to transport the blood sample sampled by the needle 8 from the blood tube 11 towards the interior of the device 2.

[0027] In the embodiment described herein, the light source 12 is preferably an LED type with an infrared wavelength in the range of 700-980 nm, particularly 800 nm, which is the iso-saturation point between oxyhemoglobin and deoxyhemoglobin, making the measurement less sensitive to blood oxygen saturation. In the embodiment described herein, the optical sensor 14 is a photodiode type and may be selected from PMT, PDA, CMOS, and other sensors. In the embodiment described herein, the tube 16 is made of Teflon and is connected to the needle 8. Alternatively, the tube 16 may be made of glass or plastic and should be selected to provide good transparency to the wavelength of the light source 12.

[0028] The light source assembly 12 and the optical sensor 14 can be seen as one sensor 20 of the second group 6. As in the example described here, they may be made as two parts that are assembled to sandwich the needle 8 (e.g., made of metal) and the tubing 16. Alternatively, the light source 12 and the optical sensor 14 may be integrated. Preferably, the sensor 20 is placed fairly close to the tip of the needle 8, less than 10 cm, to optimize shearing of the red blood cells. Preferably, this distance is about 5 cm for best results. In some variations, the sensor 20 may be placed directly at the exit of the needle 8.

[0029] Whatever its configuration, the second group 6 can advantageously use needle 8 diameters conventionally in the range of 1 mm. Indeed, during sampling by the needle 8, the red blood cells undergo a continuous deformation, as will be explained below and shown in FIG. 3.

[0030] Thus, when the needle 8 is immersed in the blood tube 11, the second group 6 controls the aspiration by the needle 8, which is already primed with diluent, in order to sample the blood. This is achieved by known automated control means, a preparation tray, a solenoid valve, and a syringe, which are not shown for simplicity. These means cause the movement of the diluent occupying the tube 16. During this step, the sensor 20 measures a constant light signal, since the tube 16 and the diluent contained therein are translucent.

[0031] An aliquot of blood is then moved by suction to the sensor 20. The red blood cells are sheared and clumps are broken down. At this step, the optical signal remains at a maximum because the blood has not yet confronted the sensor 20. In Figure 3, this is indicated by the reference numeral 30.

[0032] When the blood reaches the sensor, the optical signal represents the shear state of the blood, during which the red blood cells have an elongated shape as shown by reference numeral 31.

[0033] When suction is stopped to stop the shearing, the optical transmission signal decreases as the red blood cells return to their biconcave disk-relieved form, shown as 32 in FIG. 3. The optical signal then increases in a pseudo-logarithmic progression. The gradual increase in optical signal measured by optical sensor 14 is associated with the gradual aggregation of free red blood cells. Aggregation occurs by the red blood cells stacking and rolling, and then forming three-dimensional structures shown as 34 and 36 in FIG. 3.

[0034] After about 40 s, depending on the blood, clumping slows significantly and sedimentation begins. This onset of sedimentation interferes with the correlation between clumping, the measurement of interest, and sedimentation velocity. After t4, an aliquot of blood is removed, for example, by moving needle 8 over the tray. This removes the blood and rinses tube 16 with diluent; at the end of this step, tube 16 is completely filled with diluent, just as it was at the beginning of the procedure described hereinabove.

[0035] The four time points are shown in FIG. Before time t1, the tube 16 is filled with diluent. - Time t1 indicates the time when the blood reaches the level of the sensor 20 by suction. - Time t2 indicates the time when suction stops. - Time t3 marks the time from which the red blood cells regain their relaxed shape and begin to aggregate. - Time point t4 marks the end of the treatment with the blood being drained and replaced again by diluent, as before time point t1.

[0036] 3, it may seem paradoxical that after time t4, while tube 16 is filled with diluent, the optical signal is less significant than when tube 16 is filled with blood. This is explained in the embodiment described herein by the fact that optical sensor 14 is conditioned differently before time t1 and after time t4 in FIG.

[0037] Therefore, before time t1 and after time t4, the measurements are determined to correspond to "blank" measurements. During this period, the optical sensor 14 is adjusted by the converter 10 with a minimum measurement gain.

[0038] Time t3 corresponds to the lowest point in the period t1-t4, beyond which the optical signal begins to increase, which indicates the onset of the phenomenon the present invention is intended to measure, as described herein above. For this reason, and because the fluctuations in the optical signal remain small between time t0 and time t1, in the embodiment described herein, optical sensor 14 is conditioned at minimum gain until time t1, at maximum gain between time t1 and time t4, and again at minimum gain after time t4 for the next measurement.

[0039] This is further advantageous because in the embodiment described herein, converter 10 is arranged to determine the measurement based on the optical density of the signal measured by optical sensor 14. Here, optical density is defined by the formula DO(t)=log(KI / I(t)), where I(t) is the measurement of the optical sensor at time t and K is the maximum gain / minimum gain ratio. More specifically, converter 10 is arranged to return a sedimentation velocity measurement based on the ratio DO(t3) / DO(t4). Applicant has performed a large number of sedimentation velocity measurements using the Westergren criteria method, which allows converter 10 to relate the measurement thus calculated to an ESR value.

[0040] The applicant has found it particularly advantageous to use optical density, which allows independence from variations in transmittance measurements. The applicant has also found that the converter 10 can operate based on the ratio I(t4) / I(t3), without taking into account optical density in the Beer-Lambertian sense and without using I0 differently in the calculation.

[0041] Converter 10 may be created in various ways, such as in the form of suitable computer code running on one or more processors. By processor, we mean any processor suitable for the calculations described herein. Such processors may be created in any known manner, such as microprocessors for personal computers, laptops, tablets, or smartphones; dedicated chips of the FPGA or SoC type; grid or cloud computing resources; clusters of graphical processors (GPUs); microcontrollers; or any other form capable of providing the computing power necessary to complete the processes described herein. One or more of these elements may be created in the form of specialized electronic circuits, such as ASICs. Combinations of processors and electronic circuits are also contemplated. In the case of a gradient boosting-based machine learning unit, a dedicated processor for machine learning is also contemplated. Alternatively, converter 10 may be an analog computer without any programming or computer code.

[0042] As a further alternative, the converter 10 can use machine learning algorithms (in English "machine learning"), which may or may not include neural networks (deep or not). This involves correlating the intensity measurements of the optical sensor 14 with values ​​of sedimentation velocity. This variant may be particularly useful to implement without optical density. As a further alternative, the gain of the optical sensor 14 can be the same for all measurements.

[0043] Figure 4 is a schematic diagram showing an embodiment of the device of Figure 1. As shown in this figure, device 2 is a conventional blood testing device that includes a 1.5 mm diameter syringe 40 and a 16 mm diameter syringe 42, both of which are connected to a needle 8. Sensor 20 is integrated into needle 8 so as to cover the end of tubing 16 connected to needle 8.

[0044] Apparatus 2 of FIG. 4 is adapted to perform CBC measurements, ESR measurements, or both.

[0045] For a CBC measurement, the entire circuit is primed with diluent, the needle 8 is placed in the blood tube 11, and 10 μl is sampled with the syringe 40. The needle 8 is then lifted and placed on a preparation tray, the exterior of which is washed in this tray and expelled to waste. Finally, a mixture of 10 μL of sample and 1 mL of diluent (for example) is dispensed immediately after sampling into the preparation tray with the syringe 42. This initial diluent is then used for various preparations to perform the CBC measurement. Advantageously, once the aliquot of blood has been expelled into the preparation tray, cleaning of the interior and exterior of the needle 8 may be performed.

[0046] The ESR measurement proceeds as described herein with reference to Figures 1 to 3. The entire circuit is primed with diluent drawn from reservoir 44, and a few μL of air bubble is created at the tip of needle 8. Needle 8 is lowered into blood tube 11, and a 50 μL to 100 μL aliquot is sampled with syringe 42. Needle 8 is raised, the aliquot is transferred to sensor 20, and an optical measurement of agglutination is made. Finally, the interior and exterior of needle 8 is rinsed in a tray and drained to waste. An empty measurement (I0) may be taken before sampling or at the end of the rinse. An optional before-and-after comparison of the empty measurement allows for exception handling, e.g., rinsing control.

[0047] The CBC and ESR cycles are carried out independently of each other, in particular with separate sampling by needle 8. The aliquot for the CBC measurement cannot be used for the ESR measurement and vice versa.

[0048] A mixture of 10 μL of sample and 1 mL of diluent (for example) is dispensed immediately after sampling in the preparation tray with syringe 42. This initial diluent is then used for the various preparations for performing the CBC measurement.

[0049] This allows the two measurements to be separated without problematic blood sampling if both measurements are required. This independence means that the ESR measurement does not significantly impact the work rate of Device 2, allowing for low-cost integration in terms of both equipment and personnel.

[0050] Figure 5 is a schematic diagram of another embodiment of the device of Figure 1. As shown in this figure, the device 2 is now fitted into an automated laboratory measurement chain of the TLA (in English "Total Laboratory Automation") type.

[0051] The most expensive and complex part is the equipment required to supply the sample to the measuring cell of Device 2, including interconnections to the TLA chain, tube rack management, tube agitation, tube management, sampling and transfer in the measuring cell, cleaning of the sampling equipment, and equipment for monitoring and transmitting the results.

[0052] The applicant has found that in this configuration it is advantageous to integrate the second group 6 into a module separate from the main CBC module 50 and connect it thereto. For example, the second group 6 may be integrated into the sampling needles of group 4 of the spray or stain module 55. The utilization rate of this module is therefore increased, and the performance rate of the TLA is not affected, since the ESR measurement is again performed on a given blood tube, completely independent of the CBC measurement.

[0053] This is much more effective than known systems that offer special modules for measuring sedimentation velocity in addition to the scattering and staining modules, or that eliminate the processing time of CBC / DIF / RET with a generic module.

[0054] Alternatively, the second group 6 may be integrated into the sampling needles of high-end devices constituting a specific sampling module for subsequent scattering or coloration measurements.

[0055] Thus, the present invention allows for the effective integration of sedimentation velocity measurements into existing equipment without affecting its operating speed or architecture.

Claims

1. 1. An apparatus (2) for performing a complete blood count and determining sedimentation rate, comprising: a first module (4) arranged to sample a blood sample from the tube and perform a complete blood count on the blood sample; a second module (6) arranged to sample the blood sample from the tube and to carry out a sedimentation velocity determination, and at least one sampling member (8) that can be controlled for measurement by the first module (4) and measurement by the second module (6) to sample a blood sample so that the blood sample sampled for the first module (4) is not used by the second module (6) and the blood sample sampled for the second module (6) is not used by the first module (4), The second module (6) is provided with a sensor (20) having an infrared light source (12) and an optical sensor (14) arranged substantially opposite each other around a tube (16) connected to an output end of at least one of the sampling members (8), and light emitted by the infrared light source (12) reaches the optical sensor (14) after traversing the tube (16); the second module (6) is further arranged to perform a rinsing of the sampling member (8) and the tube (16) between two determinations of sedimentation velocity measurements; the optical sensor (14) is arranged to perform a blank measurement based on light emitted from the infrared light source (12) and traversing the tube (16) in the absence of a blood sample after a rinsing operation; The apparatus (2) further comprises a converter (10) arranged to receive the blank measurement and one or more light transmission measurements from the optical sensor (14) and to determine the sedimentation velocity from a ratio of the blank measurement and the light transmission measurement.

2. 2. The device (2) according to claim 1, wherein the second module (6) is arranged at the inlet of the device (2) upstream of the first module (4) or at the outlet of the device (2) downstream of the first module (4) for carrying out complementary measurements of the spraying or staining type.

3. 2. The device (2) according to claim 1, wherein the converter (10) is arranged to determine the time (t3) of the lowest light transmittance measurement and the time (t4) of the final light transmittance measurement.

4. 4. The apparatus (2) of claim 3, wherein the optical sensor (14) is positioned to achieve maximum gain between the time (t3) of the lowest light transmittance measurement and the time (t4) of the final light transmittance measurement, and to achieve minimum gain at other times.

5. 4. The device (2) according to claim 3, wherein the converter (10) is arranged to calculate the sedimentation velocity based on the ratio of the blank measurement to the measurement at the time (t4) of the final light transmittance measurement, on the one hand, and the ratio of the blank measurement to the measurement at the time (t3) of the lowest light transmittance measurement, on the other hand.

6. 2. The device (2) of claim 1, wherein the optical sensor (14) is controlled at a low gain before the blood passes through the substantially transparent portion and at a high gain after the blood passes through the substantially transparent portion.

7. 2. The device (2) according to claim 1, wherein the sampling member is a needle (8) that can be controlled for sampling a blood sample to which the tube (16) having a substantially transparent portion (16) is connected.

8. 1. A method for performing a complete blood count and determining sedimentation rate, comprising: The use of a device (2) according to any one of claims 1 to 7, A method wherein performing a complete blood count on the one hand and determining the sedimentation rate on the other hand comprises sampling two different blood samples.

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