Abstract: An analytical method and test composition for determining whether an analyte is present in a test sample at a predetermined concentration level by measuring or observing a preselected level of indicator response, e.g., color generation. A subtractive reaction is carried out on the test sample prior to the indicator reaction in order to stoichiometrically and specifically consume a predetermined amount of analyte. The resulting indicator reaction generates the preselected level of indicator response only if the analyte is present at the predetermined concentration level or greater. The subtractive reaction is enzymatically specific for the analyte in the reaction mixture and the amount of analyte consumed can be closely controlled by the amount of a regulating coreactant present at initiation. The method enables the determination of analyte without the need for standards or comparators, e.g., color charts, and therefore is self-indicating.

Abstract: Test compositions, indicators, and test device are provided which are capable of generating different hues at different analyte concentrations. The compositions are capable of generating a yellow hue in situ. Visual tests for clinically important analytes, such as glucose, are determined by use of two independent catalytic systems which are reactive with reduced nicotinamide adenine dinucleotide to produce a range of hues; the particular hue produced depending on the concentration of the analyte. The invention provides a test device for the determination of analyte, e.g. glucose, in body fluid which exhibits a rainbow of hues, the particular final hue produced depending on the analyte concentration.

Abstract: Test compositions and test devices are provided which are capable of generating different hues at different analyte concentrations. Visual results for clinically important analytes, such as glucose and cholesterol, are provided by use of compositions containing two independent catalytic systems which are reactive with a common substrate generated from the analyte of interest, to produce visual endpoints of different hues for different concentrations of analyte. Preferred formulations provide a RAINBOW of hues, the particular final hue produced depending on the concentration of the analyte.

Abstract: An analytical element for quantitatively determining high levels of glucose in blood is made by (a) impregnating a carrier with a first solution, having dissolved therein 4-aminoantipyrine and 3-hydroxy-2,4,6-triiodobenzoic acid or 3,5-dichloro-2-hydroxy-benzene sulfonic acid or salts thereof, a glucose oxidase and a peroxidase, and drying the carrier; and (b) applying to the carrier a second solution of a film-forming agent in a volatile solvent, and drying to remove the volatile solvent and leave a film over the dried first impregnant.