# US 5,705,396 A · Additive for diagnostic tests for determination of the coagulability of blood, method of reducing the influencing of diagnostic tests by heparin and the use of metal salts for these purposes

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- Number: US 5,705,396 A
- Document ID: US5705396A
- Status: Granted
- Kind: A
- Application number: 08/516,198
- Filed: 1995-08-17
- Granted: 1998-01-06
- Earliest claimed: 1994-08-20
- Assignees: Behringwerke Diagnostics GmbH
- Inventors: Karl Fickenscher; Norbert Zander
- Web page: https://patentgrep.com/patent/US5705396A

## CPC

- C12Q 1/56: involving blood clotting factors, e.g. involving thrombin, thromboplastin, fibrinogen
- G01N 2400/40: Glycosaminoglycans, i.e. GAG or mucopolysaccharides, e.g. chondroitin sulfate, dermatan sulfate, hyaluronic acid, heparin, heparan sulfate, and related sulfated polysaccharides
- Y10T 436/108331: Preservative, buffer, anticoagulant or diluent
- Y10T 436/25125: Digestion or removing interfering materials
- 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)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The accuracy of a diagnostic test for determining the coagulability of blood is improved by reducing the interference by heparin. At least one metal salt, preferably a copper or zinc salt, is added to the diagnostic test to avoid or considerably reduce the undesirable influence of heparin on the test.

## Claims

### Claim 1

A method of reducing the interference by heparin with the accuracy of a diagnostic test for determining the coagulability of blood, which comprises introducing an additive into at least one reagent of said diagnostic test, wherein said additive comprises at least one metal salt of copper or zinc, a copper or zinc ion of which forms a bond with heparin.

### Claim 2

A method of reducing the interference by heparin with the accuracy of a diagnostic test for determining the coagulability of blood, which comprises adding an additive to said diagnostic test, wherein said additive comprises at least one metal salt of copper or zinc, a copper or zinc ion of which forms a bond with heparin.

### Claim 3 (depends on 2)

The method as claimed in claim 2, wherein said metal salt of copper or zinc is employed in a concentration of up to 20 mM.

### Claim 4 (depends on 3)

The method as claimed in claim 3, wherein said metal salt of copper or zinc is employed in a concentration of between 50 and 500 .mu.M.

### Claim 5 (depends on 4)

The method as claimed in claim 4, wherein said metal salt of copper or zinc is zinc chloride and is employed in a concentration of 50 .mu.M.

### Claim 6 (depends on 4)

The method as claimed in claim 4, wherein said metal salt of copper or zinc is zinc chloride and is employed in a concentration of 100 .mu.M.

### Claim 7 (depends on 4)

The method as claimed in claim 4, wherein said metal salt of copper or zinc is zinc chloride and is employed in a concentration of 160 .mu.M.

### Claim 8 (depends on 4)

The method as claimed in claim 4, wherein said metal salt of copper or zinc is zinc chloride and is employed in a concentration of 200 .mu.M.

### Claim 9 (depends on 4)

The method as claimed in claim 4, wherein said additive further comprises at least one polycation.

### Claim 10 (depends on 9)

The method as claimed in claim 9, whereto said polycation is Polybrene.

### Claim 11 (depends on 10)

The method as claimed in claim 10, wherein said Polybrene is employed in a concentration of 10 mg/l, and said metal salt of copper or zinc is zinc chloride and is employed in a concentration of 100 .mu.M.

### Claim 12 (depends on 2)

The method as claimed in claim 2, wherein said diagnostic test determines thromboplastin time.

### Claim 13 (depends on 2)

The method as claimed in claim 2, wherein said diagnostic test determines thrombin time.

### Claim 14 (depends on 2)

The method as claimed in claim 2, wherein said diagnostic test determines activated partial thromboplastin time.