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] Sedimentation rate is a routine part of the complete blood count (CBC) performed in blood tests and can detect the presence of inflammatory or infectious pathologies, such as rheumatism, cancer, and other diseases that cause changes in the protein concentration in the blood. A high ESR indicates an inflammatory state, without prejudging its nature. However, the ESR may remain low during the presence of an inflammatory syndrome. Therefore, a high ESR generally indicates the presence of a pathology. Combining this nonspecific test with complementary tests allows for a more accurate diagnosis.

[0003] The standard method for ESR measurement is the Westergren method. Thin tubes with standardized dimensions are filled with blood samples 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 normal limits are not absolute and depend on the age and sex of the patient.

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

[0005] The phenomenon of red blood cell aggregation is caused by proteins in particular in blood, the higher their concentration, the greater the force they exert. The formation of aggregates means that red blood cells pile up in a "roll-like" manner, forming a three-dimensional structure. The rate of sedimentation depends on the size of the aggregate and on the viscosity of the plasma.

[0006] In the final step, the aggregates settle, i.e., they slowly 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 the aggregation phenomenon, which is directly dependent on the concentration of plasma proteins. It is this phenomenon that the present invention measures to return an ESR value. It is also a non-specific parameter, but it suppresses the interferences arising from the last two steps of the ESR. There are no standardized parameters that can express this aggregation rate or kinetics / dynamics. It is therefore important to translate the aggregation measurement to ESR.

[0008] Due to the volume of blood (1.6 ml) and the time required for completion (1 hour), the Westergren method is not compatible with hematology instruments 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 an improved ESR measurement into a hematology testing device, as described in EP2921862, in which a certain amount of blood is taken and separated into two parts, one for the count (CBC) and one for the sedimentation rate measurement.

[0010] This device therefore links the counting and sedimentation velocity measurements and is disadvantageous because it requires complex equipment to dispense portions of two blood samples, one via a single sample, towards the counting portion on one side and towards 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 an apparatus 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 analysis device including a module for measuring the erythrocyte sedimentation rate, a module for measuring a hemogram, and a sample allocation module. The sample allocation module is used to collect a blood sample and to allocate a first part of the blood sample to the erythrocyte sedimentation rate measurement module and a second part 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 capable of quickly performing complete blood counts and sedimentation rate determinations while being separated from each other and with a simple structure. Summary of the Invention

[0014] The present invention improves this situation. For this purpose, a device for performing a complete blood count and determining a sedimentation rate is provided, comprising a first group arranged to sample a blood sample from a tube and to perform a complete blood count on said sample, and a second group arranged to sample a blood sample from a tube and to perform a determination of the sedimentation rate. The device comprises at least one sampling member which can be controlled for the measurement by the first group for sampling a blood sample and for the measurement by the second group such 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 comprising a sensor comprising 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 the light emitted by the infrared light source reaches the optical sensor after traversing the tube. The second group is further arranged to perform a rinsing of the sampling member and the tube between the determination of two sedimentation rate measurements, the optical sensor being arranged to perform a blank measurement after the rinsing operation. The apparatus further comprises a converter arranged to receive the empty measurement and one or more light transmission measurements from the optical sensor and to determine the sedimentation velocity from a ratio of the empty 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, thus providing a less systematic test, but without interfering 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 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 a device for carrying out complementary measurements of the spraying or staining type. The converter is positioned to determine the time of the lowest light transmission measurement and the time of the final light transmission measurement. The optical sensor is positioned to perform a maximum gain between the time of the lowest light transmission measurement and the time of the final light transmission 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 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 on reading the following description with reference to embodiments given for illustrative and non-limiting purposes and with reference to the drawings, in which: [Brief description of the drawings]

[0019] [Figure 1] Overall schematic diagram of the device according to the present invention [Diagram 2] Detailed view of the creation of the elements in Figure 1 [Diagram 3] Measurement diagram of the device in Figure 1 [Figure 4] 2 is a schematic diagram of a first embodiment of the device of FIG. 1; [Diagram 5] Schematic diagram of a second embodiment of the device of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0021] 1 is a general schematic diagram of an apparatus 2 for performing a complete blood count and determining a sedimentation velocity measurement 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 mainly perform a complete blood count on this sample. This measurement can be performed in a conventional manner and is known elsewhere. There are many blood testing devices that specialize in this measurement. Other blood analyses than CBC can also be performed in group 4, such as glycosylated hemoglobin (HbA1c) measurement, C-reactive protein (CRP), etc.

[0023] The second group 6 is arranged to determine an 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 cumbersome or coupled with a CBC measurement, slowing down the operation of the whole device.

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

[0025] Thus, as shown in Figure 1, the first group 4 or the second group 6 controls a needle 8 to sample a blood sample in a blood tube 11. This sample is then brought to the first group 4, where a blood measurement, such as a CBC measurement, is performed, or to the second group 6, where a measurement of the change in absorbance is performed. In the last 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 made up of 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 of the LED type, preferably with an infrared wavelength in the range of 700-980 nm, in particular 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 of the photodiode type and may be selected among PMT, PDA, CMOS, etc. 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 for 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 tube 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 the shearing of the red blood cells. Preferably, this distance is about 5 cm for best results. In a variant, 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 continuous deformations, as will be explained below and shown in FIG.

[0030] Thus, when the needle 8 is immersed in the blood tube 11, the second group 6 controls the aspiration by the needle 8, already primed with diluent, in order to sample blood. This is achieved by automated control means, preparation trays, solenoid valves and syringes, which are known and are not shown for simplicity. These means cause the movement of the diluent occupying the tube 16. In 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. At this step, the optical signal remains at a maximum because the blood has not yet faced the sensor 20. In Figure 3, this is indicated by reference numeral 30.

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

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

[0034] Beyond about 40 s, depending on the blood, clumping slows considerably and sedimentation begins, which prevents the correlation of clumping with sedimentation velocity, the measurement of interest. After t4, an aliquot of blood is drained, for example by moving needle 8 over the tray, thus draining the blood and rinsing tube 16 with diluent, and at the end of this step tube 16 is completely filled with diluent as at the start of the procedure described herein above.

[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 blood reaches the level of the sensor 20 by suction. - Time t2 indicates the time when suction stops. - Time point t3 marks the point from which the red blood cells regain their relaxed shape and aggregation begins. - 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, which 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 of the period t1-t4, beyond which the optical signal begins to increase, which indicates the onset of the phenomenon that the present invention seeks to measure, as described herein above. For this reason, and because the variations in the optical signal remain small between times t0 and t1, in the embodiment described herein, the optical sensor 14 is conditioned at minimum gain until time t1, at maximum gain between times t1-t4, and again at minimum gain after time t4 for the next measurement.

[0039] This is further advantageous since in the embodiment described herein the converter 10 is arranged to determine the measurement based on the optical density of the signal measured by the optical sensor 14, where the 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, the converter 10 is arranged to return a sedimentation velocity measurement based on the ratio DO(t3) / DO(t4). The applicant has carried out a large number of sedimentation velocity measurements using the Westergren criteria method, which allows the 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 the variability of the transmission measurements. The applicant has also found that the converter 10 can also operate on the basis of 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] The converter 10 may be created in various ways, for example in the form of a suitable computer code executed on one or more processors. By processor, we mean any processor suitable for the calculations described herein. Such a processor may be made in any known manner in the form of a microprocessor for a personal computer, laptop, tablet or smartphone, a dedicated chip of FPGA or SoC type, a computing resource on a grid or on the cloud, a cluster of graphical processors (GPUs), a microcontroller, or any other form capable of providing the computing power required for the completion of the processes described herein. One or more of these elements may be made in the form of a specialized electronic circuit, such as an ASIC. A combination of a processor and an electronic circuit is also conceivable. In the case of a machine learning unit based on gradient boosting, a processor dedicated to machine learning is also conceivable. Alternatively, the converter 10 may be an analog computer without 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 the 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 at any one time.

[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 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. Sensor 20 is integrated into needle 8 so as to cover the end of tube 16 connected to needle 8.

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

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

[0046] For the ESR measurement, the procedure proceeds as described herein with reference to Figures 1 to 3. The entire circuit is primed with diluent pumped from the reservoir 44 and a few μL of air bubble is created at the tip of the needle 8. The needle 8 is lowered into the blood tube 11 and an aliquot of 50 μL to 100 μL is sampled with the syringe 42. The needle 8 is raised and the aliquot is transferred to the sensor 20 and an optical measurement of agglutination is made. Finally, the needle 8 is rinsed internally and externally 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 exception handling, e.g. control of the rinse.

[0047] The CBC and ESR cycles are performed independently of each other, in particular with separate sampling by needle 8. An aliquot for a CBC measurement cannot be used for an 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 a 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 decoupled 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 shows 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 Instrument 2, including the interconnection to the TLA chain, tube rack management, tube mixing, 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 in a module separate from the main CBC module 50 and to connect it thereto. For example, the second group 6 may be integrated into the sampling needles of group 4 of the sparging or staining module 55. The utilization rate of this module is thus increased and the working rate of the TLA is not affected, since the ESR measurement is again performed on a tube of blood, completely independent of the CBC measurement.

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

[0054] Alternatively, the second group 6 may be integrated into a sampling needle of a high-end device 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 for performing a complete blood count and determining sedimentation rate, comprising: a first group (4) arranged to take a blood sample from the tube and to perform a complete blood count on said sample; a second group (6) arranged to sample the blood sample from the tube and to carry out a determination of the sedimentation rate, at least one sampling member (8) that can be controlled for the measurement by the first group (4) and the measurement by the second group (6) for sampling a blood sample such that the sample sampled for the first group (4) is not used by the second group (6) and the sample sampled for the second group (6) is not used by the first group (4); The second group (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), such that light emitted by the infrared light source (12) reaches the optical sensor (14) after traversing the tube (16); the second group (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 an empty measurement after a rinsing operation, The apparatus further comprises a converter (10) arranged to receive an empty measurement and one or more light transmission measurements from the optical sensor (14) and to determine a settling velocity from a ratio of the empty measurement and the light transmission measurement.

2. 2. The apparatus of claim 1, wherein the infrared light source (12) and the optical sensor (14) are positioned less than 10 cm from the sampling end of the sampling member (8).

3. 3. Apparatus according to claim 1 or 2, 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 carrying out complementary measurements of the spraying or staining type downstream of the first group (4).

4. 4. Apparatus according to any one of claims 1 to 3, wherein the converter (10) is arranged to determine the time of the lowest light transmission measurement (t3) and the time of the final light transmission measurement (t4).

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

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

7. 7. The apparatus 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.

8. 8. The device 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.

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

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