Abstract: A system composed of a complex of a chelating agent with a polyvalent metal ion in its higher valency, an indicator capable of reacting with said metal ion in its lower valency and a buffering agent is disclosed as a composition and a test strip useful for colorimetric analysis of ascorbic acid present in body fluid.

Abstract: A diagnostic composition containing as a chromogen a diamino-biphenyl derivative in which at least one of the hydrogen atoms in the amino groups thereof is replaced by a lower alkyl group by reaction with an alkylating agent. The diagnosing instrument is prepared by impregnating a bibulous, porous support in a solution comprising the diagnostic composition and optionally a saccharide oxidase, peroxidase and a guaiac, and, if necessary, a buffer, a surfactant, a background adjusting dye and/or an agent for increasing the viscosity of the composition. This diagnosing instrument can be handled in a simple and convenient way and is used to identify semi-quantitatively a saccharide in body fluids or excrements of humans or animals with reliability.

Abstract: A diagnostic composition is prepared which contains as a chromogen a diamino-biphenyl derivative in which at least one of the hydrogen atoms in the amino groups thereof is replaced by a lower alkyl group by reaction with an alkylating agent. A diagnosing instrument is prepared by impregnating a bibulous, porous support in a solution comprising the diagnostic composition and optionally a saccharide oxidase, peroxidase and a guaiac, and, if necessary, a buffer, a surfactant, a background adjusting dye and/or an agent for increasing the viscosity of the composition. This diagnosing instrument can be handled in a simple and convenient way and is used to identify semi-quantitatively a saccharide in body fluids or excrements of humans or animals with reliability.