Abstract: An automatic analyzer comprising a plurality of sample containers for accommodating different blood samples individually, specific sample container moving means, a plurality of reagent containers for accommodating at least a reagent for an assay of guanase activity, a specific reagent container holding means, a plurality of reaction containers, specific reaction container moving means, specific sample pouring means, specific cleaning vessels, specific stirring means, specific measuring means, specific cleaning means, a specific analog-digital converter, specific counting-calculating means, a specific display means, and specific operation control means, so that the display means produces a signal for excluding the measured blood sample corresponding to a display value when the display value is above a predetermined reference value of guanase activity.

Abstract: The guanase activity in body fluids such as blood serum can be rapidly and accurately assayed by (I) decomposing guanine with the guanase in the specimen to xanthine and ammonia at pH 7-9, preferably at pH 8, (II) decomposing the xanthine formed by former step I with xanthine oxidase to uric acid and hydrogen peroxide, (III) reacting the reactant solution of the former step II with 3-methyl-2-benzothiazolinonehydrazone, an aniline derivative such as N,N-di-lower-alkylaniline and peroxidase, and finally measuring the optical absorption of the reactant solution of the step III at 570-600 nm. The all steps can be completed within 15 minutes. Therefore, this assay is adoptable for automatic assay of guanase on usual clinically available automatic analyzers.