Abstract: Disclosed is a novel diagnostic reagent system for the detection of hydroperoxides or substances which react with peroxidatively active substances resulting in the liberation of hydroperoxides which reagent system comprises a chromogenic oxidation indicator and a peroxidase or a peroxidatively active substance, together with an inhibitor of color generation selected from the group of 1,4-disubstituted semicarbazides, thiosemicarbazides and 1,5-disubstituted carbazides as inhibitors of color generation. By inhibiting the generation of color formed by oxidation of the chromogenic indicator, the indicator's usefulness in discriminating between varying concentrations of analyte is enhanced.

Abstract: A new and improved test device and method of determining the presence and concentration of fructosamines in a test sample. The test device includes a test pad comprising a carrier matrix incorporating an indicator reagent composition capable of interacting with fructosamines to produce a detectable or measurable response. The carrier matrix of the device includes a bibulous matrix, such as filter paper, or a nonbibulous matrix, such as a polymeric film. In addition, a new and improved indicator reagent composition comprising a dye, such as tetrazolium violet; a suitable buffer; and an accelerator compound is incorporated into the carrier matrix to provide a test pad demonstrating sufficient color resolution and having sufficient sensitivity to fructosamines in a test sample. Therefore, a fast, more accurate and trustworthy fructosamine assay of a liquid test sample, such as whole blood or serum, is achieved.