Diagnostics based on tetrazolium compounds

• US 7,144,709 B2
• Filed: 11/16/2004
• Issued: 12/05/2006
• Est. Priority Date: 09/28/1998
• Status: Expired due to Term

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Ouyang, Tianmei, Yu, Yeung Siu
• Primary Examiner(s): Le, Long V.
• Assistant Examiner(s): Do, Pensee T.
• Application Number:
  US10/990,684
• Publication Number:
  US 20050112712A1
• Time in Patent Office: 749 Days
• Field of Search: 435/7.9, 435/14, 435/26, 435/287.7, 435/287.8, 435/96.2, 435/970, 436/110, 436/537, 422/56, 422/57
• US Class Current: 435/7.9
• CPC Class Codes: C12Q 1/26 involving oxidoreductase
• CPC Class Codes: C12Q 1/32 involving dehydrogenase
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements
• CPC Class Codes: G01N 33/64 involving ketones
• 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 435/97 Test strip or test slide
• CPC Class Codes: Y10T 436/173076 Nitrite or nitrate

Abstract

A reagent is suitable for measuring the concentration of an analyte in a hemoglobin-containing biological fluid, such as whole blood. The reagent comprises a flavin-dependent enzyme that has specificity for the analyte, a flavin cofactor if, and only if, a flavin is not bound to the enzyme, a tetrazolium dye precursor, an electron transfer agent, and a nitrite salt. The reagent causes dye formation that is a measure of the analyte concentration. The nitrite salt suppresses interfering dye formation caused non-enzymatically by the hemoglobin. Preferably, the reagent is used in a dry strip for measuring glucose in whole blood.

Claims

1. A reagent for measuring a concentration of an analyte in a hemoglobin-containing biological fluid, comprising

(a) a flavin-dependent enzyme that has a specificity for the analyte and does not have a flavin bound to it,

(b) a flavin mononucleotide (FMN) or flavin adenine dinucleotide (FAD),

(c) a tetrazolium dye precursor,

(d) an electron transfer agent, and

(e) a nitrite salt.

2. The reagent of claim 1 in which the dye precursor is water-soluble.

3. The reagent of claim 1 in which the electron transfer agent comprises phenazine methosulfate (PMS) or an analog thereof.

4. The reagent of claim 1 further comprising a divalent metal stabilizer.