METHOD AND REACTIVE KIT FOR DETERMINING UREA IN BODY FLUIDS Russian patent published in 1998 - IPC

FIELD: laboratory diagnostics. SUBSTANCE: urea contained in aliquot of a body fluid is hydrolyzed by urease into ammonia. Ammonium ions emerged in aqueous solution are detected by their reaction with sodium hypochlorite alkaline solution in presence of ammonia acceptor and catalyst. The former is 4-hydroxycoumarin in the form of aqueous solution with concentration 270 to 540 mg/l. Resulting from hydrolysis ammonium ions may be determined by their reaction with 4- hydroxycoumarin or with reagent consisting of sodium hypochlorite alkaline solution, 4-hydroxycoumarin, and potassium ferricyanide as supplementary catalyst. Ready-to-use reactive forms kit designed to determine urea in body fluids contains following components: sodium nitroprusside (catalyst), alkali (concentrated solution), sodium hypochlorite (concentrated solution), and 4-hydroxycoumarin (ammonia acceptor) in the form of mixture with potassium ferricyanide. The latter mixture as well as urease and sodium nitroprusside are present in the form of tablets. EFFECT: simplified analytical procedure. 4 cl, 5 tbl, 4 ex