Apparatus and method for performing whole blood cell counting and determining sedimentation rate

Abstract

A device for diffusing or colouring and determining sedimentation rate comprises a first group (4) arranged to sample blood samples in a cuvette and to perform smear testing on the samples, and a second group (6) arranged to sample blood samples in a cuvette and to perform sedimentation rate determination. The device comprises at least one sampling member (8) controllable to operate by said first group (4) and by said second group (6) to sample blood samples such that samples collected for said first group (4) are not used by said second group (6) and samples collected for said second group (6) are not used by said first group (4), the second group (6) is equipped with a sensor (20) comprising an infrared light source (12) and an optical sensor (14), which are arranged substantially oppositely around a cuvette (16) connected to the output of the at least one sampling element (8), the light emitted by the infrared light source (12) reaches the optical sensor (14) after passing through the test tube (16). The apparatus further comprises a converter (10) arranged to receive the one or more light transmission measurements from the optical sensor (14) and to determine the settling rate.

Description

[0001] The present invention relates to the field of hematology, and more specifically to the determination of sedimentation rate (hereinafter referred to as ESR, also known in English as "erythrocyte sedimentation rate" or "ESR").

[0002] The sedimentation rate is part of the routine examination of the complete blood count (hereinafter referred to as CBC, standing for "complete blood count") performed during the blood evaluation and can detect the presence of inflammatory or infectious pathologies. For example, rheumatic diseases, cancer and other diseases that cause changes in the concentration of proteins in the blood. A high ESR indicates an inflammatory state, but does not prejudge its nature. However, when an inflammatory syndrome is present, the ESR remains low. Therefore, a high ESR usually indicates the presence of pathology. Combining this nonspecific test with complementary tests allows a more accurate diagnosis.

[0003] The reference method for measuring ESR is the Westergren method. A blood sample collected with an anticoagulant (e.g. EDTA) is placed in a standard-sized capillary tube, diluted with sodium citrate and placed vertically. The ESR measurement is the height of the plasma column in millimeters after one hour of sedimentation. For example, a height of less than 10 millimeters after one hour of sedimentation is considered normal for an adult male. Normal limits are not absolute values ​​but depend on the patient's age and sex.

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

[0005] The phenomenon of erythrocyte aggregation is caused in particular by blood proteins, whose aggregation force increases with increasing concentration. Aggregates are formed by stacking of erythrocytes into "rolls" and then into 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 sediment, i.e. they gradually fall to the bottom of the tube and compact, thus separating the sample into a clear 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 clear portion.

[0007] The most relevant inflammatory parameter is the aggregation phenomenon, which directly depends on the concentration of plasma proteins. It is this phenomenon that is measured in the present invention to return the ESR value. It is also a non-specific parameter, but it suppresses interference caused by the last two steps of the ESR. There is no standardized parameter that can express this aggregation rate or dynamics / kinetics. Therefore, it is relevant to convert the aggregation measurement into ESR.

[0008] Due to the amount of blood (1.6 ml) and the time required for completion (1 hour), the Westergren method is not compatible with hematology machines used for CBC analysis. To overcome these problems, studies have been conducted, such as in patent US 6,632,679, to determine the sedimentation rate using optical measurements of extinction (absorption and scattering).

[0009] Some patents, such as EP2921862, have proposed integrating improved ESR measurements into blood testing devices that collect a volume of blood and separate it into two parts for separate counts (CBC) and sedimentation rate measurements.

[0010] Therefore, the device links the count measurement and the sedimentation rate measurement, which is disadvantageous because it requires a complex device to distribute the two blood sample parts through one sample to the count part on one side and the sedimentation rate measurement part on the other side, especially since the CBC and ESR measurement operations do not have the same requirements in terms of sample preparation.

[0011] Document ITUA20163693A1 describes an instrument that allows hematological analysis of blood samples and allows the detection of the blood sedimentation rate (ESR) to be integrated into the detection of other chemical and physical parameters of the blood. Document WO2021 / 097610A1 describes a sample analyzer, including a module for measuring the erythrocyte sedimentation rate, a module for measuring the blood image, and a sample distribution module. The sample distribution module is used to collect a blood sample, distribute the first part of the blood sample to the erythrocyte sedimentation rate measurement module, and distribute the second part of the blood sample to the complete blood cell count measurement module. The erythrocyte sedimentation rate measurement module includes a measuring tube and an optical measuring device.

[0012] There is no known device which enables the determination of a complete blood cell count and a sedimentation rate measurement in a rapid, decoupled from one another and of simple construction.

[0013] The present invention improves this situation. To this end, it provides an apparatus for performing a complete blood cell count and determining a sedimentation rate, the apparatus comprising a first group arranged to sample a blood sample in a test tube and perform a complete blood cell count on the sample, and a second group arranged to sample a blood sample in a test tube and perform a sedimentation rate determination. The apparatus comprises at least one sampling member that can be controlled by the first group to perform measurements and by the second group to perform measurements to sample a blood sample, so that the second group does not use the sample collected for the first group and the first group does not use the sample collected for the second group, the second group being equipped with a sensor comprising an infrared light source and an optical sensor, the infrared light source and the optical sensor being arranged approximately oppositely around a test tube connected to an output end of at least one sampling member, so that the light emitted by the infrared light source reaches the optical sensor after passing through the test tube. The second group is also arranged to rinse the sampling member and the tube between two sedimentation rate measurement determinations, and the optical sensor is arranged to perform a blank measurement after the rinsing operation. The apparatus further comprises a transducer arranged to receive a blank measurement and one or more light transmission measurements from the optical sensor and to determine a sedimentation rate based on a ratio between the blank measurement and the light transmission measurements.

[0014] The device is particularly advantageous because it allows sedimentation rate measurement to be performed independently of the complete blood count. Therefore, the sedimentation rate measurement remains a less systematic test and does not interfere with the architecture of the device in a way that could affect other functions.

[0015] According to various embodiments, the present invention may have one or more of the following features:

[0016] - The infrared light source and optical sensor are arranged at a distance of less than 10 cm from the sampling end of the sampling piece,

[0017] The second group is arranged at the inlet of the device, upstream of the first group, or at the outlet of the device for carrying out complementary measurements of the diffusion or coloration type downstream of the first group.

[0018] - a converter is arranged to determine a minimum light transmission measurement point in time and a final light transmission measurement point in time,

[0019] - the optical sensor is arranged to achieve a maximum gain between the lowest light transmission measurement time point and the final light transmission measurement time point, and a minimum gain at the rest of the time,

[0020] - the converter is arranged to calculate the sedimentation rate from the ratio between the ratio of the blank measurement value and the measurement value of the final light transmission measurement time point on the one hand and the ratio of the blank measurement value and the measurement value of the lowest light transmission measurement time point on the other hand.

[0021] - the optical sensor is controlled at a low gain before the blood passes through the substantially transparent portion and at a high gain thereafter, and

[0022] The sampling member is a needle which can be controlled to collect a blood sample, the needle being connected to a test tube in which a substantially transparent portion is formed.

[0023] The invention also relates to a method for performing a complete blood count and determining a sedimentation rate, which method comprises using a device according to the invention and performing a complete blood count on the one hand and determining a sedimentation rate on the other hand comprises taking two different samples.

[0024] Other characteristics and advantages of the invention will better emerge on reading the following description, with reference to examples given for illustrative and non-limiting purposes, with reference to the accompanying drawings, in which:

[0025] - Figure 1 shows a general schematic diagram of an apparatus according to the invention,

[0026] - Figure 2 Shows Figure 1 The manufacturing details of the components,

[0027] - Figure 3 Shows Figure 1 Measurement diagram of the equipment,

[0028] - Figure 4 Shows Figure 1 A schematic diagram of a first embodiment of a device; and

[0029] - Figure 5 Shows Figure 1 Schematic diagram of a second embodiment of an apparatus.

[0030] The accompanying drawings and the following description essentially contain components of a certain nature. Therefore, they not only contribute to a better understanding of the invention, but also contribute to the definition of the invention where appropriate.

[0031] Figure 1 The overall schematic diagram of the device 2 for performing a complete blood cell count and determining a sedimentation rate measurement according to the present invention is shown. The device 2 comprises a first set 4, a second set 6, a sampling member 8 and a converter 10.

[0032] The first group 4 is arranged to take a blood sample in a test tube and to perform a complete blood cell count on the sample. This measurement can be performed in a conventional manner and is known elsewhere. Many hematology instruments are specifically designed to perform such measurements. In addition to CBC, other types of blood analysis can also be performed in group 4, such as glycated hemoglobin (HbA1c) measurement, C-reactive protein (CRP), etc.

[0033] The second group 6 is arranged to determine the ESR measurement. This second group is the main object of the present invention. In fact, as mentioned in the background introduction section, this test, whether carried out according to the conventional method or by measuring the change in light absorbance, is either cumbersome or combined with a CBC measurement, which slows down the whole device.

[0034] According to the invention, the implementation of the second set 6 allows to infer the sedimentation rate measurement by changing the light absorbance in a manner separate from any CBC measurement or other blood measurement. To this end, the second set 6 is arranged to control the sampling member 8, here a needle, independently of the first set 4, i.e. the sample collected by the first set 4 is only used for CBC measurement or other blood measurement, while the sample collected by the second set 6 is only used for ESR measurement.

[0035] Therefore, if Figure 1 As shown, the first group 4 or the second group 6 controls the needle 8 to collect a blood sample in the blood vessel 11. Afterwards, the sample is taken to the first group 4 for CBC measurement or other blood measurement, or to the second group 6 for measurement of light absorbance changes. In the latter case, the measurement result is transmitted to the converter 10, and the converter 10 returns an ESR signal and / or an ESR measurement value.

[0036] Figure 2 An embodiment of a second measurement group 6 is shown. According to this example, the second measurement group 6 is constituted by a light source 12 and an optical sensor 14 assembled relative to each other around a tube 16 for conveying a blood sample collected by a needle 8 from a blood vessel 11 to the interior of the device 2 .

[0037] In the example described herein, the light source 12 is of LED type, and its infrared wavelength is preferably in the range of 700-980 nm, in particular 800 nm, which is the isosbestic point between oxygenated hemoglobin and deoxygenated hemoglobin, which makes the measurement insensitive to blood oxygen saturation. In the example described herein, the optical sensor 14 is of photodiode type, which can be selected from sensors such as PMT, PDA, CMOS, etc. In the example described herein, the cuvette 16 is made of Teflon and is connected to the needle 8. Alternatively, the cuvette 16 can be made of glass or plastic and should be selected to provide good transparency to the wavelength of the light source 12.

[0038] The light source assembly 12 and the optical sensor 14 can be considered as a single sensor 20 of the second group 6. As in the example described herein, it can be made in two parts, assembled together to buckle the needle 8 (for example metal) and the test tube 16. Alternatively, the light source 12 and the optical sensor 14 can be made in one piece. Preferably, the sensor 20 is arranged very close to the end of the needle 8, less than 10 cm from the latter, to optimize the shearing of the red blood cells. Preferably, this distance is about 5 cm to obtain the best results. In a variant, the sensor 20 can be placed directly at the outlet of the needle 8.

[0039] Whatever the configuration, the second set 6 allows advantageous use of a diameter of the needle 8 which is generally in the range of 1 mm. In fact, during the sampling process with the needle 8, the red blood cells undergo a continuous deformation, which will be described below and as Figure 3 shown.

[0040] Thus, once the needle 8 is immersed in the blood vessel 11, the second group 6 controls the aspiration of the needle 8, which has been primed with the diluent, in order to collect the blood. This is done thanks to automated control methods, preparation trays and solenoid valves and syringes, which are also known and, for the sake of simplicity, are not shown in the figures. These methods cause the diluent occupying the test tube 16 to move. During this step, the sensor 20 measures a constant light signal due to the translucent nature of the test tube 16 and the diluent contained therein.

[0041] Afterwards, the blood aliquot is moved upward to the sensor 20 by suction. The red blood cells are sheared, thereby breaking up the aggregation. During this step, the optical signal remains at a maximum because the blood is not yet opposite to the sensor 20. Figure 3 This is indicated by reference numeral 30 .

[0042] When the blood reaches the sensor, the optical signal indicates the shear state of the blood. In this blood shear stage, the red blood cells have an elongated shape, as shown by reference numeral 31.

[0043] When aspiration is stopped to stop shearing, the optical transmission signal decreases as the red blood cells resume their biconcave disc-shaped relief form. Figure 3 In the embodiment, this is indicated by reference numeral 32. Afterwards, the optical signal increases according to a pseudo-logarithmic progression. The gradual increase in the optical signal measured by the optical sensor 14 is associated with the gradual aggregation of free red blood cells. Aggregation is accomplished by stacking red blood cells to form a roll and subsequent three-dimensional structure, which is achieved in Figure 3 In the drawings, reference numerals 34 and 36 are used to indicate the same.

[0044] After about 40 seconds, depending on the blood, aggregation slows down considerably and sedimentation begins. The onset of sedimentation interferes with the measurement of interest, namely aggregation and its correlation with sedimentation rate. After t4, the blood aliquot is drained, for example by moving the needle 8 to a tray. Thus, draining the blood and flushing the test tube 16 with the diluent continues, at the end of which the test tube 16 is completely filled with diluent, just as at the beginning of the above-described procedure.

[0045] Figure 3 Four time points are shown:

[0046] - before time point t1, the test tube 16 is filled with diluent,

[0047] - time point t1 marks the time point when the blood reaches the level of the sensor 20 by aspiration,

[0048] - time point t2 marks the time point when the suction is stopped,

[0049] - Time point t3 marks the point in time when erythrocytes regain their relaxed shape and begin to aggregate,

[0050] - Time point t4 marks the end of the procedure, when the blood is drained and replaced again by the diluent, just as before time point t1.

[0051] Figure 3 The observation that after time t4, when the cuvette 16 is filled with diluent, the optical signal is less important than when the cuvette 16 is filled with blood seems somewhat paradoxical. This is explained by the fact that in the example described herein, the optical sensor 14 is Figure 3 The adjustment methods before time point t1 and after time point t4 are different.

[0052] Therefore, before the time point t1 and after the time point t4, the determined measured values ​​correspond to “blank” measured values. During this period, the optical sensor 14 is regulated by the converter 10 with the minimum measurement gain.

[0053] The time point t3 corresponds to the lowest point of the period t1-t4, beyond which the optical signal begins to increase, which, as described above, marks the beginning of the phenomenon that the present invention is intended to measure. For this reason, and since the variation of the optical signal remains low between the time point t0 and the time point t1, in the example described herein, the optical sensor 14 is regulated with minimum gain until the time point t1, then with maximum gain between the time point t1 and t4, and then again with minimum gain after the time point t4 for the next measurement.

[0054] This is even more advantageous because in the embodiments described herein, the converter 10 is arranged to determine the measurement value based on the optical density of the signal measured by the optical sensor 14. It should be recalled that the optical density is defined by the formula DO(t)=log(KI0 / I(t)), where I(t) is the measurement value of the optical sensor at time point t and K is the maximum gain / minimum gain ratio. More specifically, the converter 10 is arranged to return a sedimentation rate measurement value based on the DO(t3) / DO(t4) ratio. The applicant performed a number of sedimentation rate measurements using the Westergren reference method, which enabled the converter 10 to correlate the measurement value calculated therefrom with the ESR value.

[0055] The applicant has found that the use of optical density is particularly advantageous, which makes it independent of any variations in the transmittance measurement. The applicant has also found that the converter 10 can also operate based on the ratio I(t4) / I(t3) without having to consider the optical density in the Beer-Lambert sense and using I0 in a different way in the calculation.

[0056] The converter 10 can be made in various ways, such as in the form of a suitable computer code executed on one or more processors. The processor should be understood as any processor suitable for the calculations described below. Such a processor can be made in any known way, such as a microprocessor of a personal computer, laptop, tablet or smart phone, a dedicated chip of the type FPGA or SoC, a computing resource in a grid or cloud, a graphics processor (GPU) cluster, a microcontroller, or any other form that can provide the computing power required to complete the process described below. One or more of these elements can also be made in the form of a dedicated electronic circuit (such as an ASIC). A combination of a processor and an electronic circuit can also be considered. In the case of a machine learning unit based on gradient boosting, a processor dedicated to machine learning can also be considered. Alternatively, the converter 10 can be an analog computer without any programming or computer code.

[0057] Alternatively, the converter 10 may use a machine learning algorithm, which may or may not involve a neural network (deep or non-deep). This involves correlating the intensity measurement of the optical sensor 14 with the sedimentation rate value. This variant may be particularly suitable for the case where there is no optical density. Alternatively, the gain of the optical sensor 14 may be the same for all time points of the measurement.

[0058] Figure 4 Shows Figure 1 Schematic diagram of an embodiment of a device. As shown, the device 2 is a conventional hematology device, including a syringe 40 with a diameter of 1.5 mm and a syringe 42 with a diameter of 16 mm, both of which are connected to a needle 8. The sensor 20 has been integrated on the needle 8 so that it covers the end of the test tube 16 connected to the needle 8.

[0059] Figure 4 The device 2 is suitable for performing CBC measurements, ESR measurements, or both.

[0060] For the CBC measurement, the entire circuit is primed with the diluent, then the needle 8 is inserted into the blood vessel 11 and 10 microliters are sampled with the syringe 40. Afterwards, the needle 8 is lifted and placed on the preparation tray, where the outside of the needle is then rinsed and discharged to waste. Finally, immediately after sampling in the preparation tray with the syringe 42, a mixture of 10 microliters of sample and 1 milliliter of diluent (for example) is dispensed. This first dilution will then be used for a different preparation for the CBC measurement. Advantageously, the internal and external flushing of the needle 8 can be performed once the blood aliquot has been discharged into the preparation tray.

[0061] For ESR measurements, it is performed as described above and refers to Figures 1 to 3 . The entire circuit is pretreated with a diluent drawn from the reservoir 44, and then a few microliters of bubbles are generated at the tip of the needle 8. The needle 8 is placed in the blood vessel 11, and an aliquot of 50 to 100 microliters is collected by the syringe 42. The needle 8 is lifted and the aliquot is transferred to the sensor 20 and an optical measurement of the aggregate is performed. Finally, the needle 8 is internally and externally flushed in the tray and the discharge is discharged into the waste liquid. A blank measurement (I0) can be performed before sampling or at the end of flushing. The blank measurements before and after can optionally be compared to enable abnormal handling, such as flushing control.

[0062] The CBC and ESR cycles are performed independently of each other and notably involve separate sampling of needle 8: an aliquot for CBC measurement cannot be used for ESR measurement and vice versa.

[0063] After sampling in the preparation tray with syringe 42, a mixture of 10 microliters of sample and 1 milliliter of diluent (for example) is dispensed immediately. Later, this first dilution will be used for a different preparation for CBC measurement.

[0064] This allows the two measurements to be separated without any problematic blood sampling when they are needed. This independence makes measuring ESR much less cumbersome to the device 2's workload and can be integrated at a lower cost, both in terms of instrumentation and manpower.

[0065] Figure 5 Shows Figure 1 As shown in the figure, the device 2 is now suitable for an automated laboratory measurement chain of the TLA (English for "Total Laboratory Automation") type.

[0066] The mandatory equipment for feeding the sample into the measuring unit of the device 2 is by far the most expensive and complex part: interconnection with the TLA chain, management of the test tube rack, stirring of the test tubes, management of the test tubes, sampling and transfer in the measuring unit, flushing of the sampling device and equipment for monitoring and transmitting the results.

[0067] The Applicant has found that, in this configuration, it is advantageous to integrate the second set 6 into a module separate from and connected to the main CBC module 50. For example, the second set 6 can be integrated into the sampling needles of the set 4 of the diffusion or staining module 55. Thus, the utilization of this module will be increased, and the working rate of the TLA will not be affected, since the ESR measurement will here again be carried out completely independently of the CBC measurement of a given vessel.

[0068] The device of the present invention is much more efficient than all known systems which, in addition to providing diffusion or staining modules, also provide specific modules for measuring sedimentation rate or save CBC / DIF / RET processing time on a universal module.

[0069] Alternatively, the second set 6 may be integrated on a sampling needle of a high-end device comprising a specific sampling module for subsequent diffusion or colorimetric measurements.

[0070] The present invention thus allows sedimentation rate measurements to be efficiently integrated into existing equipment without affecting its operating rate or structure.

Claims

1. An apparatus for performing a complete blood cell count and determining a sedimentation rate, comprising a first group (4) arranged to take a sample of blood from a test tube and perform a complete blood cell count on the sample, characterized in that It comprises a second group (6) arranged to sample a blood sample in a test tube and to determine the sedimentation rate, the device comprising at least one sampling element (8) which can be controlled by the first group (4) for measurement and by the second group (6) for sampling a blood sample, so that a sample collected for the first group (4) is not used by the second group (6), and a sample collected for the second group (6) is not used by the first group (4), the second group (6) being equipped with a sensor (20), the sensor (20) comprising an infrared light source (12) and an optical sensor (14), the infrared light source (12) and the optical sensor (14) surrounding a device connected to the at least one sampling element (8). The test tube (16) at the output end of the sample piece (8) is arranged approximately opposite to each other so that the light emitted by the infrared light source (12) reaches the optical sensor (14) after passing through the test tube (16). The second group (6) is also arranged to rinse the sampling piece (8) and the test tube (16) between two sedimentation rate measurements, and the optical sensor (14) is arranged to perform a blank measurement after the rinsing operation. The device also includes a converter (10), which is arranged to receive a blank measurement value and one or more light transmission measurement values ​​from the optical sensor (14) and determine the sedimentation rate based on the ratio between the blank measurement value and the light transmission measurement value.

2. The device according to claim 1, wherein The infrared light source (12) and the optical sensor (14) are arranged at a position less than 10 centimeters away from the sampling end of the sampling member (8).

3. The device according to any one of the preceding claims, wherein: The second group (6) is arranged at the inlet of the device (2), upstream of the first group (4), or at the outlet of the device (2) for performing complementary measurements of the diffusion or coloration type downstream of the first group (4).

4. The device according to any one of the preceding claims, wherein: The converter (10) is arranged to determine a minimum light transmission measurement time point (t3) and a final light transmission measurement time point (t4).

5. The device according to claim 4, wherein: The optical sensor (14) is arranged to achieve a maximum gain between a minimum light transmission measurement time point (t3) and a final light transmission measurement time point (t4), and to achieve a minimum gain at the remaining time.

6. The device according to claim 4 or 5, wherein: The converter (10) is arranged to calculate the sedimentation rate based on the ratio between the ratio of the blank measurement value and the measurement value of the final light transmission measurement time point (t4) on the one hand and the ratio of the blank measurement value and the measurement value of the minimum light transmission measurement time point (t3) on the other hand.

7. The device according to any one of the preceding claims, wherein: The optical sensor (14) is controlled at a low gain before blood passes through the substantially transparent portion and at a high gain thereafter.

8. The device according to any one of the preceding claims, wherein The sampling member is a needle (8) which can be controlled to collect a blood sample. The needle is connected to a test tube (16), and a substantially transparent portion (16) is formed in the test tube (16).

9. A method for performing a complete blood cell count and determining a sedimentation rate, characterized in that The method comprises the use of a device according to one of claims 1 to 8 and is characterized in that carrying out a complete blood cell count on the one hand and determining the sedimentation rate on the other hand comprises taking two different samples.

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