The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 18, 1992
Filed:
May. 25, 1990
Thomas N Stewart, Durham, NC (US);
Glenn P Vonk, Fuquay-Varina, NC (US);
James P Mapes, Raleigh, NC (US);
Becton, Dickinson and Company, Franklin Lakes, NJ (US);
Abstract
A method for enzyme immunoassay of a ligand includes urease as a label. A bound fraction of ligand and antiligand conjugated to urease is formed on a solid support. The urease component of the bound fraction is contacted with a substrate composition for urease which includes a compound converted to ammonia by the urease, a tetrazolium salt and a pH dependent reducing agent which reduces the tetrazolium salt when the pH of the assay medium has been raised by the ammonia. The tetrazolium salt is reduced to a colored insoluble formazan which precipitates as a detectable spot on the support. The invention includes the substrate composition and a kit of materials for performing the assay.