JPS582750A - Method and device for measuring blood coagulation time - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining the clotting time of a blood sample, wherein a sample-reagent mixture is formed by introducing the sample and at least one reagent into a cupette; It also relates to a device suitable for carrying out this method.

Method equipment of the above type (West German utility model GM7707546
) is known, where the coagulation of the sample-reagent mixture is brought about by stirring the mixture with a stirring bar, which must be introduced into the cuvette before the measurement and which is placed outside the cuvette. It is driven by a magnetic stirring device.

When a large number of measurements are to be carried out, the expense of labor for introducing the stirrer into the cube has been found to be a drawback of the above-mentioned known method. Since magnetic stirring devices represent a significant portion of the total material cost of known devices, it is further desirable to have a device that will work without such devices.

The problem underlying the invention is therefore to obtain a method, a device of the above type, which requires low labor and material costs.

According to the invention, this problem is solved by the tear method cited earlier, which involves moving the sample-reagent mixture in a stationary cuvette so that the mixture flows forward and backward around the edges that project into the stationary cuvette. There is a stage where a blood clot forms on this edge.

A further object of the invention is an apparatus for measuring the clotting time of a blood sample with a Kupets F receiving the sample and reagent. In the device according to the invention, the upper part of the kuvette is divided into two chambers by a partition, the partition having an edge placed at a certain distance from the bottom of the kuvette.

Compared to the above-mentioned known methods and corresponding devices, the solution obtained according to the invention has the advantage that there is no need to introduce a stirrer into the cuvette and therefore no drive for this stirrer is required. The invention can therefore significantly reduce labor and material costs.

An example of the operation of the present invention will now be described with reference to the accompanying drawings.

FIG. 1 shows a cuvette used in the device according to the invention. The cupette is made of a material that allows the contents of the cupette to be measured optically. This cuvette does not have to be of the type shown in Figure 1. However, it is essential to have the partition 2 with sharp edges 3Tt-. This partition divides the upper part of the cupette into two chambers 7.8.

The device also houses a light source 5 (e.g. a light emitting diode) and a light receiver 6 (e.g. a photoelectric diode) within the device shown in FIG. Due to these elements, the luminous flux 4 passing through Kupets F
are produced and received, respectively, so that the luminous flux becomes luminous flux 4
Because it is possible to measure the absorption of light in the contents of the cuppet that crosses it,
Pass near and under edge 3. The path of the light bundle 4 is left in such a way that the blood clot 33 formed on the edge 3 is traversed by the light bundle 4.

Additionally, the device houses a light source 62 (eg, a light emitting diode 62) and a light receiver 63 (eg, a photoelectric diode 63) within the device shown in FIG. These elements create and receive, respectively, a beam of light 61 passing through the cup, so that the beam passes over the rim 3 in order to be able to measure the light absorption of the contents of the cup F traversed by the beam. The path of the beam 61 is such that the maximum amount of sample introduced into the cuvette is not detected by the beam 61, but even if a minimum volume is chosen for the sample-reagent mixture, after adding the reagent this mixture is selected to be crossed by.

In order to reduce the influence of ambient light when measuring the light absorption in the beams 4, 61, it is preferable to use a photodiode with an integrated infrared II filter as the receiver. The filter range of the latter filter is preferably from about 900 mm to 1000 mm, with a minimum attenuation at about 940 mm. These filters make the measurements approximately five times less sensitive to incandescent ambient illumination.

As shown in FIG. 2, the upper chamber T of the kvet>1 is connected by an opening 9 to a device 21, by means of which a variable air pressure can be created acting on the contents of the kvet. This pressure causes the sample-reagent mixture within the device according to the invention to move as shown in FIG. 3(3). As will be explained later with reference to FIGS. 7 and 8, the device 21 can have, for example, a vibrating membrane 22 as a pumping element. The air pressure generated thereby passes through the tube 23 and the opening S into the tappet 1, which has an opening 11 which remains open during operation.

As shown in FIG. 3, the following steps are performed in the operation of the method according to the invention with the device described above.

(1) A predetermined volume of blood or plasma sample 31 is introduced into the cupet and cultured therein.As shown in FIG. , is therefore preferably chosen to be small enough so that air can flow freely between the sample surface and the edge 3. Device 2
The air pressure generated at 1 cannot therefore move the sample, which remains stationary, unless a predetermined amount of reagent is introduced into the tube.

(8) A predetermined amount of reagent is introduced into the cupette. The respective amounts of sample and reagent are chosen such that the side of the sample-reagent mixture lies in each case above the edge 3 and the beam 61. The following effects are thereby achieved as soon as the reagent is introduced into the cupette.

(3) The sample-reagent mixture is detected by the light beam 61.

This point marks the start of clotting time measurements. This point coincides with electronic signal processing devices known per se.

Due to the action of the air pressure, which occurs in the apparatus shown in FIG. 2, the sample-reagent mixture now flows and thereby moves forward and backward between the positions ←) and (b) shown in FIG. 3 (3). Thereby the sample is well mixed with the reagents and a flow of the mixture around the sharp edges 3 of the cuvette occurs.

(4) Due to the relative movement of the liquid with respect to the edge 3 shown in (3), a blood clot 33 forms on the edge 3 at the moment of coagulation.

Since this blood clot is detected by the light beam 4, an abrupt and perceivable change in the light absorption measured with this light beam results. By measuring this change, the coagulation time becomes clear at the same time as the coagulation time, and can be measured correctly. For this measurement, an electronic signal processing device or data recording device, which is known per se, is used to record the determined values.

As a variant of the above method, and provided that the measurements are not impaired thereby, the sample volume can also be chosen to be large enough so that only the sample is placed in the cuvette with its side on the edge 3. In this case, the sample is traversed by a beam of light 4, similar to that shown in FIG. 3 for the same sample-reagent mixture, before the reagents are added to the sample and moved under the action of air pressure as described above.

As shown in Tables 4 to 6b, the device according to the invention can work in a cupette of the stationery type.

FIG. 4a is a sectional view of the coupe 41 shown in side view in FIG. 4b. As in the case of the cupette 1 of FIG. 1, the cupette 41 also has a partition 44 with sharp edges 43. Kubetsu) 41 top W & 45 are open. As shown in FIG. 5, variable air pressure is supplied to the cupet 41 through a lateral opening 42, which is connected via a tube 77 to a device for producing air pressure.

Compared to the cupet according to FIG. 1, the cuvette 41 of FIGS. 4a to 6b has the advantage that it is easier to operate, since it can be easily placed in the measuring device.

FIG. 6a shows the cupette 41 containing only the sample. Figure 6b shows the container containing the sample-reagent) 41
It shows. In FIGS. 6a and 6b, the position of the light beam 4.61 is each indicated by a small circle.

The mode of operation of the device according to the invention with the cuvette 41 according to FIGS. 4a and 4b is the same as described above on the basis of FIG.

7@I shows a diagrammatic cross-sectional view of a preferred embodiment of the device 21 (FIG. 1) for creating variable air pressure. This device is housed within a housing T1. Membrane 72 with a core of steel plate 73
is placed within this housing 71. The vibrations of the membrane T2 are caused by an electromagnetic drive assembly, which is connected to the magnetic core 7.
4 and a magnetic coil 75, to which a suitable alternating current is applied.

This creates a variable air pressure in the housing 71, which air pressure is applied to each of the two cuplets of the device according to the invention.
It is added via r and rs.

FIG. 8 diagrammatically shows a typical change over time in the air pressure produced by the apparatus shown in FIG. 7. The air pressure varies between +2 mbar and 12 mbar, and its variation over time has an approximately sinusoidal shape with a frequency of approximately 40 hertz.

The above example of operation operates with a sample volume of, for example, 100 or 200 microliters and a defined reagent volume of 200 microliters.

[Brief explanation of the drawing]

FIG. 1 shows the cupette of the device according to the invention and the electro-optical device provided therein, and FIG. Showing a cross section with the making equipment:. FIG. 3 shows the steps of carrying out the method according to the invention, 4a
6b to 6b show variants of the cupette and their use in the device according to the invention, and FIG. 7 shows a schematic cross-sectional view of a preferred embodiment of the device I2 shown in FIG. 2 for creating a variable air pressure. , 1118 schematically shows a typical change over time in the air pressure that can be created with the apparatus shown in FIG. 1...Kuppet, 2...Partition, 3...Edge, 4...
・Light-15...Light source, 6...Receiver, 7, 8...
Chamber, S...opening, 11...opening, 21...device,
22... Membrane, 23...; Tube, 31°°・Sample, 33.
...Blood clot, 41...Kuppet, 42...Aperture, 43
...rim, 44...partition, 45 river top. 61... Luminous flux, 62 River light source, 63... Light receiver, T1
...housing, 72...membrane, 73,74...core, T5...coil, 77.78...tube. 4 agents: Hiromura Kōgai Fig, I Fig, 2

Claims (1)

[Claims] (1) A method for measuring coagulation time of a blood sample, comprising:
A measurement method in which a sample-reagent mixture is formed by introducing the sample and at least one reagent into a stationary container (1,41 ) a method for measuring blood coagulation time, comprising the step of moving said mixture to flow back and forth around a rim (3, 43) projecting into said cuvette, whereby a clot forms on said rim. (z) A method for measuring blood coagulation time according to claim 1, wherein the mixture is moved by air pressure. (8) In the method for measuring blood coagulation time according to claim '1, the start of the coagulation time measurement is detected by measuring a change in light absorption that occurs as a result of adding the reagent to the sample. , the light absorption is caused by the edges (3, 4
3) A blood coagulation time measurement method in which measurement is performed using a first beam of light (61) passing above. (4) In the method for measuring blood coagulation time according to claim 1, the formation of a blood clot (33) WI formed on the edge (3, 43) causes the light absorption of the sample-reagent mixture to A method for measuring blood coagulation time, which is detected by measuring with a second beam of light (4) passing through the cupet (1), said beam passing close to and below the edge (3). (5) In an apparatus for measuring the coagulation time of a blood sample using a cuvette (1) that receives the sample and at least one reagent, the upper part of the cuvette is divided into two chambers - (7, 8) by a partition <2.44. ), said partition having edges (3, 43) placed at a certain distance from the bottom of said cuvette. (6) In the blood coagulation time measuring device according to claim 5, one of the upper chambers of the cupette is connected to the device 1 (21) through an opening (9, 42), and the device A variable air pressure can be created, by which the liquid contained in the cupette is controlled so that the height of the liquid is high enough that air can flow freely between the height and the edge (3). A blood coagulation time measurement device that can be used when it is not possible. ()) In the blood coagulation time measuring device according to claim 5, the device has a first light source (62) and a first light receiver (63), and the light source and the light receiver are connected to the cuvette (63). 1, 41), a first beam of light (61) emerging from said first light source and received by said first receiver passes through said cuvette, said first beam of light passing over said edge (3, 43). blood clotting time measurement device. (8) In the blood coagulation time measuring device according to claim 5, the device is provided with
a second light source (5) and a second light receiver (6) arranged with respect to the second light source (5), a second light beam (4) emitted from the second light source and received by the second light receiver passes through the cupet; The second light beam passes near and below the edge (3, 43) of the blood coagulation time measuring device. (9) In the blood coagulation time measuring device according to claim 8, the path of the second light beam (4) is selected such that the blood clot (33) formed at the edge is detected by this light beam. Blood coagulation time measurement device.