HU186336B - Process and apparatus for determining parameter characterizing volumetric distribution of blood cells - Google Patents

Abstract

The invention relates to a method and a device for determining a characteristic of the volume distribution of blood cells parameter. Their goal is to free the evaluation of the volume distribution of subjective influences and to increase the separation accuracy between healthy and pathological distributions. It was based on the task of developing a method and a device which determine the above-mentioned parameters, which are independent of the average cell volume. The method consists of the following steps: the acquisition of cell volumes by the electronic pulse method, the classification of the blood cells according to their cell volume, the relativization of the classified cell numbers, the calculation of the average cell volume, the quotient of the sum of the relative, classified cell numbers and the average cell volume and the limit rating of this Qoutient. The apparatus according to Fig. 1 includes the following elements: a particle pulse detector (1), an analog gate (2), a pulse control circuit (3), a pulse width limiter (4), a pulse height discriminator (5), a pulse peak hold circuit (6), an A / D converter (7), a 64-channel memory (8), an address selector (9), a memory control circuit (10), a circuit for relativising and summing the channel pulse numbers (11), a circuit for calculating the MCV (12), a circuit for quotient formation (13), a limit gate (14), a setpoint generator (15), a multiplexer (16), an interface circuit (17), an interface control circuit (18) and display units (19; 20; 21).

Description

The present invention relates to an apparatus for determining a parameter for the volume distribution of blood cells. Hematology instruments can be used to test patients' blood conditions in medical laboratories. The curve of the volume distribution of blood cells and the parameters derived therefrom enable the physician to recognize the pathological change in the blood and its possible causes.

Individual instruments such as VEB Transformatoren- und Röntgenwerk Dresden TÚR ZG2 Blood Cell Counter and Medicor Works' Laborscale PSL-1 Particle Counter and 'PSA-14' Particle Unit Analyzer are known, as well as devices for hematology, VEB MLW Labortechnik Ilmenau and Medicor Works, Budapest joint PHA-1 hematology analyzer, Technicon H 6000 manufactured by Technicon Instruments Inc., USA, and Coulter Electronics LTD, UK. model "Model S-Plus" type.

Determining the volume distribution of RVD red blood cells by conductivity measurement in a measuring nozzle is based on obtaining pulses corresponding to the volume of red blood cells and classifying it with a multichannel pulse amplitude analyzer.

Channel pulse numbers are printed and / or represented as a distribution curve. The curves are evaluated mainly by optical comparison with the curves of healthy subjects. This method is highly dependent on the subjectivity of the evaluators. In addition, it does not include discriminatory evaluation based on curve parameters that can be characterized by sound medical judgment. Therefore, it is necessary to find suitable parameters and to detect them by measuring technology. As a possible step in this direction, we can consider the width of the distribution of RDW red blood cells, as determined, for example, by "H 6000" and "Model-S Plus" instruments. The red blood cell distribution width is a numerical expression of the red blood cell distribution width. This value is obtained by analogue calculation and compared to the standard deviation of MCV cell volume.

The procedure for determining the red blood cell distribution width, according to the manufacturer of the Model-S Plus instrument, consists of the following steps: The number of all red blood cells is scanned with a continuously adjustable threshold circuit. The upper threshold is continuously reduced from 360 femoliters equivalent until it contains 20 percent of all red blood cells, which is greater than a specified value of blood cell volume. This value is recorded as 20 percent. The lower threshold is lowered until they reach a value that contains 80 percent of red blood cells. The cell volume at which this occurs is recorded as 80 percent.

The width of distribution of RDW red blood cells is proportional to the proportion of total red blood cells that is between 20 percent and 80 percent, and can be expressed as follows:

(20-80) Percent Volume RDW = - 100-K (20 +80) Percent Volume where K is a validation constant that ensures that the result is equal to ten for a normal distribution. The RDW parameter depends on the MCV average cell volume of the cell population.

If the MCV value is high, an RDW value that is (likely) higher than the real one will be determined, which increases the blurring between the healthy and pathological range of the parameter. This increases the risk of false positive or false negative claims or diagnoses. Based on this, the RDW parameter is inadequate for a reliable diagnosis and is not suitable for automatic selection of pathologic blood cell distributions for further evaluation.

The object of the present invention is to separate the assessment of blood cell volume distribution from subjective factors, to improve the accuracy of the separation between healthy and pathological distributions, and to select pathological distributions for further evaluation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus for determining a volume distribution characteristic of blood cells that is independent of mean cell volume, and to automatically distinguish and label the pathological distribution as known, using this parameter.

In order to solve this problem, we have developed an apparatus comprising a pulse-generating pulse recording and processing circuit, a multi-channel pulse amplitude analyzer, a sorted and summed cell counting and display control unit, and a display circuit according to the invention. connected to a multi-channel repository and a circuit for comparing and summing the number of classified cells. The input of the quotient circuit is connected to a circuit for comparing and summing the number of classified cells and an average cell volume calculation circuit, while the output of the quotient circuit is connected to the display control unit and the first input of the threshold gate. The second input of the threshold gate is connected to a circuit comparing and summing the number of classified cells, while its output is connected to a display control unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be described in detail with reference to the drawings, in which: Figure 1 is a block diagram of the apparatus according to the invention and Figure 2 shows the relative width of red blood cell distribution in several groups of persons.

As an exemplary embodiment (Figure 1), the volume distribution of red blood cells was chosen. As the red blood cells pass through the measuring nozzle of a particle pulse detector 1, electrical impulses are produced whose amplitude corresponds to the volume of the blood cells. Impulse generation is not error free. For example, too large impulses are produced when blood cells pass through the nozzle periphery. Close or successive or transient blood cells produce overlapping pulses. Impulse pulses may occur in the pulse sequence. To eliminate these sources of error, particle3

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The pulses 6 are processed, i.e., subjected to error analysis, by means of a circuit group formed by a pulse amplitude discriminator 5, a pulse width limiter 4, a pulse control circuit 3, an analog gate 2 and a pulse peak support circuit 6. This group of circuits, the particle impulse detector 1 and the analog-to-digital converter 7 generate a pulse recording and processing unit. The analog gate 2 only transmits pulses that do not exceed a specified amplitude and width, but are larger than a lower threshold. The amplitudes of the transmitted pulses are stored in the pulse peak holding circuit 6 until they are drawn by the analog-to-digital converter 7. The 7 analog-to-digital converters digitize these amplitudes. The digital pulses, after being retrieved by 9 address selectors, address 8 multichannel stores. The recipient channel corresponds to the digitized pulse amplitude. The storage control circuit 10 then applies the current count pulse to the destination channel. The multi-channel storage 8, the address selector 9 and the storage control circuit 10 form a multi-channel pulse peak analyzer. For generating the counting pulses, the storage control circuit 10 is directly connected to the pulse amplitude discriminator 5. During each measurement, as many count pulses are stored in each channel as the number of valid pulses from the corresponding red blood cells in the corresponding volume (volume) class. The outputs of the multichannel storage 8 are directed to a channel pulse counting and summing circuit 11 and an average cell volume calculation 12. Channel Pulse Ratio consists of generating RVDCH channel percentages relative to the highest channel pulse rate.

The percentage of the channel with the highest number of clock pulses is always one hundred.

In addition, in a circuit comparing and summing all channel pulse rates, the RVDCH channel percentages are summed, resulting in the RVDPS sum of the channel percentages.

For calculating the MCV mean cell volume, the channel pulse number comparison and summing circuit 11 is connected to the mean cell volume 12 calculation circuit.

The calculation includes summing the RVDCH channel percentages multiplied by the CH channel number, then dividing this sum by the RVDPS sum of the RVDCH channel percentages and multiplying by the authentication constant K representing the volume range per channel.

The circuit for comparing and summing channel impulse numbers 11 is provided with additional outputs for its results. The channel percentages are fed to one of the inputs of the threshold gates 14, and the sum of all channel percentages is applied to the first input of the quotient circuit 13. The second input of the quotient circuit 13 is led to the output of the average cell volume 12 and to the multiplexer 16. The quotient forming circuit divides the RVDPS sum of the RVDCH link percentages and the MCV average cell volume. The BRVD parameter thus determined is called the relative width of the red blood cell volume distribution.

BRVD =

RVDPS

MCV (2RVDCH) ² i = l

K · 2RVDCH CHi i = l

The quotient circuit 13 is coupled to the multiplexer 16 and the threshold gate 14. The third output of the limit gate 14 is led to a setpoint generator 15. If the specified relative width exceeds the set default value, which is an empirical value, then the threshold gate 14 gives the channel percentages to the multiplexer 16. The multiplexer 16 is connected via an interface 17 to an analog display unit 19, a digital display unit 20 and a data recording unit 21, where the analog display unit 19 can be, for example, a writer or oscillograph, the data recording unit 21 may be a printer or punch. The interface control circuit 18 is provided with outputs for connecting the storage control circuit 10 to the respective control inputs of the multiplexer 16 and the interface 17. The interface control circuit 18 mainly controls the output of data as well as its subsequent retrieval capability. The multiplexer 16, the interface 17 and the interface control circuit 18 together form a display control unit.

The relative widths of the volume distribution of red blood cells found in a large number of individuals are plotted above the corresponding MCV values (Figure 2). The unit of the parameter is 1 fi ^-1 . Individuals can be divided into three groups; 22 healthy, 23 patients and 24 newborns. The BRVD values of the 22 healthy and the newborn 24 are relatively close to each other, although a narrow range of values can be obtained for the 22 healthy and 24 newborns. The mean values of the two ranges are slightly different, but distinguishable, which refers to the available resolution. The BRVD values of the 23 patients are highly variable and almost invariably exceed the BRVD values of the 22 healthy subjects. The fall in BRVD values of 23 patients over the 22 healthy subjects' BRVD ranges is explained by the fact that not all patients have pathologic RVD values. There is a sharp demarcation between healthy and pathological ranges. The corresponding limit 25 is set in the default value generator 15 as a default value. Figure 2 shows that there is no correlation between BRVD values and MCV values, so that the BRVD value has its own diagnostic significance.

Claims (1)

An apparatus for determining a volume distribution parameter of a blood cell, comprising a pulse-derived pulse recording and processing circuit, a multichannel pulse amplitude analyzer, and a classifying and comparing circuit for the number of classified cells, comprising: (8) and interconnected by a circuit for comparing and summing the number of classified cells (11), an input of a quotient circuit (13) to a circuit for comparing and summing the number of classified cells (11) and calculating a mean cell volume. 3186336 is connected to a circuit (12), the output of the quotient circuit (13) is connected to a display control unit having a multiplexer (16), an interface (17), an interface control circuit (18) and a first input of a limit gate (14). the second input of the boundary gate (14) is connected to a circuit comparing and summing the number of classified cells (11), while the output of the boundary gate (14) is formed by the multiplexer (16), the interface (17) and the interface control circuit (18). is connected to a display control unit.