USE OF 3,5-DICHLORO-2-HYDROXYBENZENESULFONIC ACID-4-AMINOPHENAZONE CHROMOGENIC SYSTEM IN DIRECT ENZYMIC ASSAY OF URIC-ACID IN SERUM AND URINE

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 26  (2) , 227-231
Abstract
A new direct colorimetric procedure for uric acid assay in serum or urine is described, utilizing a 3,5-dichloro-2-hydroxybenzene sulfonic acid/4-aminophenazone chromogenic system in the presence of horseradish peroxidase (EC 1.11.1.7) and uricase (EC 1.7.3.3) from Aspergillus flavus. This chromogen system has a high absorptivity, affording useful results with sample/reagent volume ratios as low as 0.025. The procedure is applicable to serum, plasma, or diluted urine. A single working reagent is used; the reaction is complete in less than 15 min at room temperature. The red dye formed is measured at 520 nm; a blank sample measurement is not needed. The standard curve for the method is linear for uric acid concentrations up to 1500 .mu.mol/l. Average analytical recovery of uric acid in human sera and urine exceeded 99%; within-run and between-run precision studies showed CV''s [coefficients of variation] of .ltoreq. 1.2 and .ltoreq. 2.2%, respectively. The new procedure correlated well with the uricase/catalase and uricase/UV methods. The method is suitable for automation.