# US 9,518,286 B2 · Method for assaying plasminogen in a liquid medium, associated compositions and kit

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- Number: US 9,518,286 B2
- Document ID: US9518286B2
- Status: Granted
- Kind: B2
- Application number: 14/198,072
- Filed: 2014-03-05
- Published: 2014-07-03
- Granted: 2016-12-13
- Earliest claimed: 2011-09-07
- Assignees: Sysmex Corporation
- Applicants: Sysmex Corporation
- Inventors: Jean Amiral
- Web page: https://patentgrep.com/patent/US9518286B2

## CPC

- C12Q 1/56: involving blood clotting factors, e.g. involving thrombin, thromboplastin, fibrinogen
- G01N 33/86: involving blood coagulating time {or factors, or their receptors}
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- 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)

## Abstract

The invention relates to a method for assaying plasminogen in a sample comprising a step consisting in particular of reacting a streptokinase (R1), and a streptokinase activator, with a control solution or a diluted plasma sample, in which the streptokinase activator is selected from the group comprising a fibrin DD fragment and/or at least one DD fragment derivative. The invention also relates to a liquid composition, a plasminogen assay kit for implementing this method and the use of a streptokinase activator selected from the group comprising a fibrin DD fragment and/or at least one DD fragment derivative.

## Claims

### Claim 1

A method for assaying plasminogen in a sample comprising steps consisting of:
a) storing a composition comprising a streptokinase and a streptokinase activator in a ready-to-use solution;
b) reacting the composition with a control solution or a diluted plasma sample;
c) tracking said reaction;
d) determining the amount of plasminogen in the control solution or in the diluted plasma sample, as a function of the result of the tracking of said reaction, wherein the streptokinase activator is a fibrin DD fragment, at least one DD fragment derivative, or both a fibrin DD fragment and at least one DD fragment derivative.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the reaction step b) is performed in the presence of an anticoagulant.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the storage step is performed at a temperature of between −20° C. and 37° C.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the storage step is performed for a period greater than 12 hours.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising before the reaction step b), a step of pre-incubating the composition comprising the streptokinase and the streptokinase activator, at around 37° C.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the reaction step b) is performed at around 37° C.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the reaction step b) is stopped by an acidification step.

### Claim 8

A method for assaying plasminogen in a sample comprising:
storing a composition comprising streptokinase and a streptokinase activator in a ready-to-use solution;
reacting the composition with a control solution or a diluted plasma sample;
tracking the reaction of the streptokinase and the streptokinase activator with the control solution of the diluted plasma sample; and
determining an amount of plasminogen in the control solution or in the diluted plasma sample based on the result of the tracking of the reaction,
wherein the streptokinase activator is at least one selected from the group consisting of a fibrin DD fragment and at least one DD fragment derivative.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the tracking step is performed by using a chromogenic substrate specific for plasmin and plasmin-streptokinase complexes.

### Claim 10 (depends on 8)

The method according to claim 8, wherein the reaction step is performed in the presence of an anticoagulant.

### Claim 11 (depends on 8)

The method according to claim 8, wherein the storage step is performed at a temperature of between −20° C. and 37° C.

### Claim 12 (depends on 8)

The method according to claim 8, wherein the storage step is performed for a period greater than 12 hours.