Apparatus for diffusion or tinting and determination of sedimentation rate

Abstract

An apparatus for diffusion or staining and determination of sedimentation rate, comprising a first group (4) arranged to sample and perform a smear test on a blood sample in a test tube, and a second group (6) arranged to sample and perform a sedimentation rate determination on a blood sample in a test tube. The apparatus comprises at least one sampling member (8) which is controllable by said first group (4) and by said second group (6) to sample a blood sample, such that the sample taken for said first group (4) is not used by said second group (6) and the sample taken for said second group (6) is not used by said first group (4), said second group (6) being equipped with a sensor (20) comprising an infrared light source (12) and an optical sensor (14), said infrared light source (12) and said optical sensor (14) being arranged substantially opposite each other around a test tube (16) connected to an output of said at least one sampling member (8), such that light emitted by said infrared light source (12) reaches said optical sensor (14) after passing through said test 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 rate.

Description

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

[0002] The sedimentation rate is part of the routine examination of a complete blood count (hereinafter CBC, for "complete blood count") performed during the evaluation of blood, which can detect the presence of inflammatory or infectious pathologies. For example, rheumatological diseases, cancers and other diseases that cause changes in the concentration of proteins in the blood. A high ESR indicates an inflammatory state, but it is not possible to prejudge its nature. However, the ESR remains low when there is an inflammatory syndrome. Therefore, a high ESR generally indicates the presence of a pathology. A more accurate diagnosis can be made by combining this non-specific test with complementary examinations.

[0003] The reference method for measuring the ESR is the Westergren method. The blood sample, taken with an anticoagulant (for example EDTA), is loaded into a thin tube of standard size and diluted with sodium citrate and placed vertically. The ESR measurement is the height of the plasma column after one hour of sedimentation, in millimeters. For example, a height of less than 10 millimeters after one hour of sedimentation is considered normal for an adult male. The normal limit is not an absolute value, but depends on the age and sex of the patient.

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

[0005] The aggregation phenomenon of red blood cells is produced in particular by the blood proteins, whose aggregation power increases with the concentration. The formation of aggregates is the stacking of red blood cells into "rolls", which are then stacked into a three-dimensional structure. The sedimentation rate depends on the size of the aggregates and the viscosity of the plasma.

[0006] In the last step, the aggregates sediment, i.e. they gradually fall to the bottom of the test tube, then compact, thus separating the sample into a top transparent part (plasma) and a much darker bottom part (red blood cells). The ESR is measured by the height of the transparent part.

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

[0008] The Westergren method is not compatible with the hematology machines used for CBC analysis due to the quantity of blood (1.6 ml) and the time required for completion (1 hour). To overcome these problems, research has been carried out, for example in patent US 6,632,679, to determine the sedimentation rate using extinction optical measurements (absorption and scattering).

[0009] Some patents, such as EP 2921862, have proposed integrating an improved ESR measurement into a blood testing device that collects a quantity of blood and divides it into two parts, one for counting (CBC) and one for sedimentation rate measurement.

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

[0011] More generally, in automated laboratories of the TLA (for "Total Laboratory Automation") type, the tube flow is managed in a fully automated way, from the most frequent tests to the least frequent ones. The instrument required to provide the sample to the measurement unit is by far the most expensive and complex part, comprising:

[0012] - interconnections with the chain,

[0013] - management of the test tube rack,

[0014] - stirring of the test tube,

[0015] - management of the test tube,

[0016] - sampling and transfer in the measurement unit,

[0017] - flushing of the sampling equipment, and

[0018] - equipment for controlling and transmitting the results.

[0019] Furthermore, this leads to a very high ratio (higher than 100) between the cost of the measurement system and the cost of the infrastructure required to manage the samples. By contrast, for a CBC / DIF / RET measurement system or an automatic diffusion or coloring system commonly used in hematology laboratories, the ratio is much lower (2 to 5).

[0020] On the other hand, laboratories that process a large number of test tubes per day require a limited processing time (Turn Around Time or TAT) for new test tubes, which directly affects the size of the CBC / DIF / RET measurement system and therefore its hardware cost.

[0021] On the other hand, since a small fraction of the processed test tubes requires diffusion or staining (only 5% to 20%), all manufacturers generally oversize the system.

[0022] Document WO2021 / 097610A1 describes a sample analyzer comprising a module for measuring the erythrocyte sedimentation rate, a module for measuring the blood picture and a sample distribution module. The sample distribution module is used to collect a blood sample, to distribute a first portion of the blood sample to the erythrocyte sedimentation rate measurement module and to distribute a second portion of the blood sample to the complete blood count measurement module. The erythrocyte sedimentation rate measurement module comprises a measurement tube and an optical measurement device.

[0023] Under the requirements of modern laboratories, no known device is able to effectively determine the sedimentation rate measurement in a fast and integrated manner.

[0024] The present invention improves this situation. To this end, it provides a device for diffusion or staining and determination of the sedimentation rate, comprising a first group arranged to sample and perform a smear test on a blood sample in a test tube, and a second group arranged to sample and perform a sedimentation rate determination from a blood sample in a test tube. The device comprises at least one sampling member, which is operable by the first group and by the second group 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, which are arranged substantially opposite each other around the test tube connected to the output of the at least one sampling member, so that the light emitted by the infrared light source reaches the optical sensor after passing through said test tube. The second group is also arranged to flush 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 flushing operation. The device 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 rate from the ratio between the blank measurement and the light transmission measurements.

[0025] The device is particularly advantageous because it allows the sedimentation rate measurement to be performed independently of the complete blood count. The sedimentation rate measurement is therefore still a less systematic test, which does not interfere with the architecture of the device in a way that could affect other functions.

[0026] According to various embodiments, the invention can have one or more of the following features:

[0027] - the infrared light source and the optical sensor are arranged at a distance of less than 10 centimeters from the sampling end of the sampling member,

[0028] - the second set is arranged at the inlet of the device, upstream of the first set, or at the outlet of the device, for a complementary measurement of the diffusion or colouring type downstream of the first set.

[0029] - the converter is arranged to determine a minimum light transmission measurement time point and a final light transmission measurement time point,

[0030] - the optical sensor is arranged to implement a maximum gain between the minimum light transmission measurement time point and the final light transmission measurement time point, and a minimum gain at the other times,

[0031] - the converter is arranged to calculate the sedimentation rate as a ratio between, on the one hand, the ratio of the blank measurement value and the measurement value of the final light transmission measurement time point, and, on the other hand, the ratio of the blank measurement value and the measurement value of the minimum light transmission measurement time point.

[0032] - the optical sensor controls with a low gain before the passage of the blood through the substantially transparent portion, and with a high gain thereafter, and

[0033] - the sampling member is a needle, which can be controlled for the collection of the blood sample, the needle being connected to a test tube in which the substantially transparent portion is formed.

[0034] The invention also relates to a method for diffusing or colouring and determining the sedimentation rate, characterised in that it comprises the use of a device according to the invention, and in that the diffusing or colouring on the one hand and the determination of the sedimentation rate on the other hand comprise the collection of two different samples.

[0035] Other characteristics and advantages of the invention will emerge better on reading the following description, given by way of example and for illustrative and non-limiting purposes, with reference to the appended drawings in which:

[0036] - Figure 1 a general schematic view of a device according to the invention is shown,

[0037] - Figure 2 manufacturing details of the components of Figure 1 are shown,

[0038] - Figure 3 a measurement diagram of the device of Figure 1 is shown, and

[0039] - Figure 4 a schematic view of an embodiment of the device of Figure 1 is shown.

[0040] The drawings and the following description essentially contain components of certain nature. They therefore not only contribute to a better understanding of the invention, but also, where appropriate, to the definition of the invention.

[0041] Figure 1 A general diagram of the device 2 for performing a complete blood count and determining a sedimentation rate measurement according to the application is shown. The device 2 comprises a first group 4, a second group 6, a sampling member 8 and a converter 10.

[0042] The first group 4 is arranged to perform a blood smear test. Devices that automatically perform blood smear tests are very common in laboratories that have to process a large number of test tubes every day. Their processing rate is generally oversized with respect to the needs of the laboratory.

[0043] This oversized size is directly related to the technical complexity of the different steps required to prepare the slide of each device (sampling, depositing a drop of the aliquot on the slide, spreading, slide identification, vital staining, etc.): the high rate is the only means for the manufacturer to optimize marginal costs.

[0044] Since the blood smear test is a less systematic test than the CBC, the Applicant found it interesting to concentrate the resources of the first group 4 in order to add the determination of the ESR measurement by the second group 6.

[0045] The second group 6 is arranged to determine the ESR measurement. This second group is the main purpose of the application. Indeed, as mentioned in the background section, this test, whether it is performed according to the conventional method or by measuring the variation of the optical absorbance, is either tedious or combined with the CBC measurement, which slows down the entire device.

[0046] According to the application, the implementation of the second group 6 allows inferring the sedimentation rate measurement by varying the optical absorbance in a separate manner from any CBC measurement or other blood measurement. To this end, the second group 6 is arranged to control the sampling member 8 independently of the first group 4, the sampling member being here a needle, i.e. the sample taken by the first group 4 is only used to perform the blood smear test, while the sample taken by the second group 6 is only used for the ESR measurement.

[0047] Thus, as Figure 1 shown, the first group 4 or the second group 6 controls the needle 8 to take a blood sample in the blood vessel 11. Afterward, this sample is taken to the first group 4 to perform the blood smear test, or to the second group 6 to measure the variation of the optical absorbance. In the latter case, the measurement result is transmitted to the converter 10, which returns the ESR signal and / or the ESR measurement.

[0048] Figure 2 An embodiment of the second measurement group 6 is shown. According to this example, the second measurement group 6 is composed of a light source 12 and an optical sensor 14, which are assembled opposite each other around a test tube 16 for transporting the blood sample taken by the needle 8 from the blood vessel 11 to the inside of the device 2.

[0049] In the examples described herein, the light source 12 is of the LED type, with an infrared wavelength preferably in the range 700-980 nm, in particular 800 nm, which is the isosbestic point between oxy- and deoxy-hemoglobin, which makes the measurement insensitive to the blood oxygen saturation. In the examples described herein, the optical sensor 14 is of the photodiode type, which can be chosen among PMT, PDA, CMOS, etc. In the examples 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 chosen to provide good transparency to the wavelength of the light source 12.

[0050] The light source assembly 12 and the optical sensor 14 can be considered as one single sensor 20 of the second group 6. As described in the examples herein, it can be made in two parts, assembled together to hold the needle 8 (e.g. metal) and the cuvette 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 shear of the red blood cells. Preferably, the distance is about 5 cm for best results. In a variant, the sensor 20 can be placed directly at the outlet of the needle 8.

[0051] Whatever the configuration, the second group 6 allows advantageously to use the diameter of the needle 8, which is usually in the range of 1 mm. Indeed, during the sampling with the needle 8, the red blood cells undergo a continuous deformation, which will be described below and illustrated in Figure 3 .

[0052] 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 diluent, in order to collect the blood. This is due to the automated control method, the preparation tray and the solenoid valve and the syringe, which are also known and are not shown in the figures for simplicity. These methods cause the diluent occupying the cuvette 16 to move. During this step, the sensor 20 measures a constant optical signal due to the translucent nature of the cuvette 16 and the diluent contained therein.

[0053] Afterwards, the blood aliquot moves upwards by aspiration to the sensor 20. The red blood cells are sheared, thus breaking the aggregation. During this step, the optical signal remains maximum since the blood is not yet opposite the sensor 20. Figure 3 This is represented by reference 30.

[0054] When the blood reaches the sensor, the optical signal is indicative of the shearing state of the blood. During this shearing phase of the blood, the red blood cells have an elongated shape, as illustrated by reference 31.

[0055] When the aspiration is stopped to stop the shearing, the optical transmission signal decreases since the red blood cells recover their biconcave discus relief form. During this phase, the optical signal is indicative of the aggregation state of the blood. This is represented by reference 32. Figure 3In this case, this is indicated with reference 32. After that, the optical signal increases according to a pseudo-logarithmic progression. The gradual increase of the optical signal measured by the optical sensor 14 is related to the gradual aggregation of the free red blood cells. Aggregation is accomplished by stacking the red blood cells to form a roll and the subsequent three-dimensional structure, which is shown in Figure 3 In this case, this is indicated with reference 34 and 36.

[0056] Depending on the blood, after more than about 40 seconds, aggregation slows down considerably and starts to sediment. The start of sedimentation interferes with the measurement of interest, i.e. aggregation and its correlation with the sedimentation rate. After t4, the blood aliquot is discharged, for example by moving the needle 8 to the tray. Therefore, the blood continues to be discharged and the test tube 16 is flushed with diluent, at the end of this step the test tube 16 is completely filled with diluent, just like at the beginning of the procedure described above.

[0057] Figure 3 The four time points are shown in the following:

[0058] - before time point t1, the test tube 16 is filled with diluent,

[0059] - time point t1 marks the time point at which the blood reaches the level of the sensor 20 by aspiration,

[0060] - time point t2 marks the time point at which aspiration is stopped,

[0061] - time point t3 marks the time point at which the red blood cells recover their relaxed shape and start to aggregate,

[0062] - time point t4 marks the end of the procedure, at which point the blood is discharged and is replaced again by diluent, just like before time point t1.

[0063] Figure 3 The observation that after time point t4, when the test tube 16 is filled with diluent, the optical signal is less important than when the test tube 16 is filled with blood, seems paradoxical. This is explained by the fact that in the example described herein, the optical sensor 14 is adjusted differently before time point t1 and after time point t4. Figure 3 The adjustment of the optical sensor 14 before time point t1 and after time point t4 is different.

[0064] Therefore, before time point t1 and after time point t4, the measured values correspond to "blank" measurements. During this period, the optical sensor 14 is adjusted by the converter 10 with a minimum measurement gain.

[0065] The time point t3 corresponds to the lowest point of the cycle t1-t4, beyond which the optical signal starts to increase, marking, as mentioned above, the beginning of the phenomenon the present invention aims 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 a minimum gain until the time point t1, then with a maximum gain between the time points t1 and t4, and then again with a minimum gain after the time point t4 for the next measurement.

[0066] This is even more advantageous because, in the embodiment 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 the 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 has made several sedimentation rate measurements using the Westergren reference method, which has enabled the converter 10 to correlate the measurement values thus calculated with ESR values.

[0067] The Applicant has found that the use of optical density is particularly advantageous, which makes it independent of any variation 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 within the Beer-Lambert meaning and use I0 in a different way in the calculation.

[0068] The converter 10 can be made in various ways, for example in the form of suitable computer code executed on one or more processors. The processor is understood to be any processor suitable for the calculations described below. Such a processor can be made in any known way, for example a microprocessor of a personal computer, a laptop, a tablet or a smartphone, a dedicated chip of the FPGA or SoC type, a computing resource in a grid or in the cloud, a cluster of graphic processors (GPUs), a microcontroller or in any other form capable of providing the computing power necessary to complete the processes described below. One or more of these elements can also be made in the form of a dedicated electronic circuit, for example an ASIC. A combination of processors and electronic circuits 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.

[0069] Alternatively, the converter 10 can use a machine learning algorithm (in English "machine learning"), which can or not involve neural networks (deep or not). This includes associating the intensity measurements of the optical sensor 14 with the sedimentation rate values. This variant can be particularly suitable in the absence of optical density. Alternatively, the gain of the optical sensor 14 can be the same for all time points of the measurement.

[0070] Figure 4 A schematic view of an embodiment of the device of Figure 1 is shown. As illustrated, the device 2 is a conventional hematology apparatus comprising a syringe 40 of 1.5 mm diameter and a syringe 42 of 16 mm diameter, both 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.

[0071] Figure 4 The device 2 of

[0072] To perform a smear test on the first set 4, the whole circuit is primed with diluent, then the needle 8 is inserted into the blood vessel 11 and a sample of about 75 microliters is taken with the syringe. During its lifting, the exterior of the needle 8 is progressively rinsed by the flow of liquid pushed to one side and continuously sucked in and expelled to the other side waste.

[0073] Afterwards, the syringe performs a liquid column removal in order to transfer an aliquot at the Y level of the pinch valve 44 opened on the side of the needle 8. The pinch valve is activated to close the channel originating from the needle 8 and to open the channel towards the drop needle 46. Afterwards, the syringe performs a push allowing the transfer of the sample to the drop needle. A series of peripheral rinses of the drop needle then dries can ensure the quality of the initial front end of the aliquot. Finally, a few microliters of drop are deposited on the slide 48 by pushing the syringe.

[0074] For the ESR measurement, it is performed as described above and with reference to Figures 1 to 3 . The whole circuit is pre-treated with diluent drawn from the reservoir 44, then a few microliters of air bubble are created at the tip of the needle 8. The needle 8 is put into the blood vessel 11 and an aliquot of 50 to 100 microliters is taken by the syringe 42. The needle 8 is lifted and the aliquot is transferred to the sensor 20 and an optical measurement of the aggregates is performed. Finally, the needle 8 is internally and externally rinsed in the tray, the effluent being discharged into the waste. A blank measurement (10) can be performed before sampling or at the end of the rinsing. Optionally, the blank measurements before and after are compared, thus enabling an abnormality treatment, for example a rinsing control.

[0075] The smear test and the ESR cycle are performed independently of each other and in particular involve a separate sampling of the needle 8: the aliquot of the smear test cannot be used for the ESR measurement and vice versa.

[0076] This allows to separate the two operations when two measurements are required without any problematic blood sampling. This independence makes the measurement of the ESR much less cumbersome for the working rate of the device 2 and enables integration at lower cost, both in terms of equipment and manpower.

[0077] The device of the application is much more efficient than all known systems which, in addition to providing a diffusion or staining module, provide a specific module for measuring the sedimentation rate or save CBC / DIF / RET processing time on a general module.

[0078] Alternatively, the second set 6 can be integrated on the sampling needle of a high-end device comprising a specific sampling module for subsequent diffusion or staining measurements.

[0079] The application thus allows to efficiently integrate the sedimentation rate measurement into existing devices without affecting their working rate or structure.

Claims

1. An apparatus for diffusion or staining and determination of sedimentation rate, comprising a first group (4) arranged to sample and perform a smear test on a blood sample in a test tube, characterized in that, It comprises a second group (6) arranged to sample from a blood sample in a test tube and to carry out a sedimentation rate determination, the device comprising at least one sampling member (8) which is controllable by the first group (4) and by the second group (6) to sample a blood sample, such that the sample taken by the first group (4) is not used by the second group (6) and the sample taken by the second group (6) is not used by the first group (4), the second group (6) being equipped with a sensor (20) comprising an infrared light source (12) and an optical sensor (14) arranged substantially opposite each other around a test tube (16) connected to an output of the at least one sampling member (8), such 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) being further arranged to flush the sampling member (8) and the test tube (16) between two sedimentation rate measurement determinations, and the optical sensor (14) being arranged to carry out a blank measurement after the flushing operation, the device further comprising a converter (10) arranged to receive a blank measurement value and one or more light transmission measurement values from the optical sensor (14) and to determine a sedimentation rate from the ratio between the blank measurement value and the light transmission measurement value.

2. The apparatus of claim 1, 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).

3. The apparatus of claim 2, wherein, The optical sensor (14) is arranged to achieve a maximum gain between the minimum light transmission measurement time point (t3) and the final light transmission measurement time point (t4) and a minimum gain at all other times.

4. The apparatus of claim 2 or 3, wherein, The converter (10) 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 (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.

5. The apparatus of claim 1, wherein, The optical sensor (14) is controlled with a low gain before the blood passes through a substantially transparent portion of the test tube (16) and with a high gain thereafter.

6. The apparatus of claim 1, wherein, The sampling member (8) is a needle which is controllable for taking a blood sample, the needle being connected with a test tube (16) in which a substantially transparent portion is formed.

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