FIELD: diagnostics. SUBSTANCE: the present innovation deals with diagnostics due to applying tetrazolium-based reagent to measure concentration of analyzed substance in hemoglobin-containing biological liquid such as whole blood. The suggested reagent includes dehydrogenase enzyme of specificity towards analyzed substance, NAD or NAD derivative, precursor of tetrazolium dyestuff, diaphorase enzyme or its analog and nitrite. The present reagent causes development of dyestuff that indicates concentration of analyzed substance. Nitrite suppresses obstacles in developing dyestuff being non enzymatically hemoglobin-caused ones. This reagent is predominantly applied in a dry strip to detect the content of ketonic bodies, such as beta-hydroxybutyrate and others. The present innovation enables to conduct reaction quickly. Moreover, it is an oxygen-insensitive one. EFFECT: higher efficiency and accuracy of diagnostics. 18 cl, 5 dwg, 1 ex, 2 tbl
