FIELD: biochemical analysis. SUBSTANCE: invention relates to diagnostics using a reagent for measuring concentration of a compound being analyzed in a body fluid containing hemoglobin, such as whole blood. This reagent includes enzyme dehydrogenase specific for this compound, pyrroloquinolinequinone or its derivative, tetrazole dye precursor, enzyme diaphorase or analogue, and nitrite salt. This reagent initiates formation of dye, which is measure of object compound concentration. Nitrite salts suppresses hemoglobin-caused nonenzymatic analysis-complicating dye formation. This reagent is advantageously used in a test strip to determine ketone bodies such as betahydroxybutyrate and others. EFFECT: accelerated test, which is insensitive to oxygen presence. 14 cl, 7 dwg, 3 tbl
