# US 4,575,492 A · Process and device for the detection and quantification of agglutinates

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- Number: US 4,575,492 A
- Document ID: US4575492A
- Status: Granted
- Kind: A
- Application number: 06/602,509
- Filed: 1984-04-20
- Granted: 1986-03-11
- Earliest claimed: 1983-05-02
- Assignees: Le Materiel Biomedical; Commissariat a l'Energie Atomique
- Inventors: Pierre David; Jean A. Jarricot
- Web page: https://patentgrep.com/patent/US4575492A

## CPC

- G01N 21/82: producing a precipitate or turbidity
- G01N 2021/5934: {Averaging on a zone}
- G01N 2201/04: Batch operation; multisample devices
- Y10S 436/805: Optical property
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The present invention relates to a process and device for the detection and quantification of agglutinates, in recipients of which at least the bottom are transparent. According to the invention, it is decided that there is agglutination when, at the same time, the calculated mean value of the bottom of the reaction studied is higher than that of a reference sample and when there exist points of measurement whose transmission is less than said threshold, and, on the other hand, that there is no agglutination when, at the same time, this calculated mean value is not greater than that of said reference sample and when there exist no points of measurement whose transmission is less than said threshold. The invention is more particularly applicable to immunohaematology.

## Claims

### Claim 1

Process for the detection and quantification, in recipients of which at least the bottoms are transparent, of reactions of agglutinations capable of being produced, under the action of at least one liquid reagent, by particles in suspension in doses of liquids to be tested contained in said recipients, comprising: observing by transparency the bottoms of said recipients containing the possible aggluintates, at n.times.m points of measurement distributed over a rectangular or square surface occupying the greater part of the surface of the bottom of each recipient; measuring the light transmission of a plurality of points of a reference sample in which no agglutination has taken place; determining a light transmission threshold which is connected with the mean value of transmission of said plurality of points of measurement of said reference sample; measuring the light transmission of a plurality of points of a test liquid; calculating the mean value of the transmission of the points of measurement whose transmission is greater than said threshold; comparing this mean value with that of said reference sample; and determining, on the one hand, that there is agglutination when, at the same time, this mean value of the transmission is higher than that of said reference sample and when there exists points of measurement whose transmission is less than said threshold, and, on the other hand, that there is no agglutination when, at the same time, this mean value is not greater than that of said reference sample and when there exists no points of measurement whose transmission is less than said threshold.

### Claim 2 (depends on 1)

The process of claim 1, wherein, in order to determine said threshold, the bottom of a recipient which is identical to the reaction recipients but which contains a reference sample not subject to agglutination is observed by transparency, at a plurality of points of meausrement, the transmission of each point of measurement is compared with an arbitrary reference and the number of points of meaurement for which the transmission is less than said reference is counted, this number of points counted is compared with a predetermined number of ordinarily-encountered parasitic points having weak transmission, then if this number of points counted is greater than said predetermined number, the value of said reference is progressively readjusted until the number of points counted is less than said predetermined number of points.

### Claim 3 (depends on 1)

The process of claim 1, wherein the points of measurement whose transmission is less than said threshold are counted.

### Claim 4 (depends on 1)

The process of claim 1, wherein, in order to determine said threshold, the bottom of a recipient which is identical to the reaction recipients but which contains a reference sample not subject to agglutination is observed by transparency at a plurality of points of measurement, the points whose transmission is higher than 50 percent are counted, the transmissions of the points whose transmission is higher than 50 percent are summed, and the mean value of the transmission of said points is calculated.

### Claim 5 (depends on 4)

The process of claim 4, wherein, in order to obtain said threshold, a certain predetermined percentage of transmission, which takes into account normally encountered parasitic points having weak transmission, is deducted from the mean value thus obtained.

### Claim 6

Device for the detection and quantification, in recipients of which at least the bottoms are transparent, of agglutinates capable of being formed, under the action of at least one liquid reagent, by particles in suspension in doses of liquids to be tested contained in said recipients, said device comprising:
(a) an arrangement of a plurality of photosensitive elements observing by transparency the bottoms of said recipients containing the possible agglutinates so as to form n.times.m points of observation distributed over a rectangular or square surface occupying the greater part of the surface of the bottom of each recipient;
(b) comparison means of which one input is connected to said photosensitive elements, of which the other input receives a signal representative of a light transmission threshold and of which the output is connected to counting means counting the points of measurement of which the transparency is less than said threshold;
(c) peak value detection means connected to said photosensitive elements;
(d) summation means receiving the output signal from said peak value detection means and summing the peak values of the signals emitted by said photosensitive elements when the response of the latter corresponds to a transmission greater than said threshold;
(e) means for memorizing the sum furnished by said summation means;
(f) means for counting the points of measurements whose transparency is greater than said threshold; and
(g) a microprocessor connected to said counting means and to said memorizing means in order to calculate, for each recipient, the mean value of the sum recorded in said memorizing means, to compare this calculated mean value with the corresponding mean value of a reference sample and to determine that there is agglutination when, at the same time, this calculated mean value is higher than that of said reference sample and when there exists points of measurement whose transparency is less than said threshold and, on the other hand, that there is no agglutination when, at the same time, this calculated mean value is not greater than that of said reference sample and when there exists no points of measurement whose transmission is less than said threshold.