Reducing tyramine interference in immunoassays for amphetamine and methamphetamine

• US 5,573,955 A
• Filed: 06/05/1995
• Issued: 11/12/1996
• Est. Priority Date: 06/05/1995
• Status: Expired due to Fees

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Microgenics Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Medlin, Theresa, Khanna, Pyare
• Primary Examiner(s): Spiegel, Carol A.
• Application Number:
  US08/465,366
• Time in Patent Office: 526 Days
• Field of Search: 435/7.1, 435/7.9, 435/7.92-7.95, 435/212, 435/228, 435/191, 435/962, 436/501, 436/545, 436/175, 436/816, 436/822, 436/825, 436/901
• US Class Current: 436/501
• CPC Class Codes: C12Q 1/26 involving oxidoreductase
• CPC Class Codes: G01N 33/5306 Improving reaction conditions, e.g. reduction of non-specific binding, promotion of specific binding
• CPC Class Codes: Y10S 435/962 Prevention or removal of interfering materials or reactants or other treatment to enhance results, e.g. determining or preventing nonspecific binding
• CPC Class Codes: Y10S 436/816 Alkaloids, amphetamines, and barbiturates
• CPC Class Codes: Y10S 436/822 Identified hapten
• CPC Class Codes: Y10S 436/825 Pretreatment for removal of interfering factors from sample
• CPC Class Codes: Y10S 436/901 Drugs of abuse, e.g. narcotics, amphetamine
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials

Abstract

A method for reducing or eliminating tyramine interference from amphetamine and methamphetamine immunoassays, comprising treating the sample with aqueous tyramine oxidase for a time and at a temperature and pH sufficient to deaminate any tyramine present in the sample, is provided.

Claims

1. In an immunoassy method for determining amphetamine or methamphetamine in a biological sample suspected of containing said amphetamine or methamphetamine, wherein any tyramine present in said sample would interfere with said determination, the improvement comprising treating said sample with an amount of tyramine oxidase sufficient to reduce interference from said tyramine in said immunoassay.

2. The method of claim 1 wherein said tyramine oxidase is added to said sample prior to performing said immunoassay.

3. The method of of claim 1 wherein said amount of tyramine is at least about 1×

10^-4 units/ml of said sample.

4. The method of claim 1 wherein the pH of a mixture of said tyramine oxidase and said sample is in the range of about 4 to 10.

5. The method of claim 1 wherein treating said sample is carried out at a temperature in the range of about 15°

to 40°

C. for a time in the range of about 5 minutes to 4 hours.

6. In a for carrying out an immunoassay to detect amphetamine or methamphetamine in a sample, the improvement comprising

treating said sample to be assayed with an amount of tyramine oxidase inthe range of about 1×

10^-4 to 10 units/ml of said sample.

7. The method of claim 6 wherein said tyramine oxidase is added to said sample prior to carrying out said immunoassay.