Abstract: An assay device and method for determining the concentration of an analyte in a fluid sample. The device includes a porous-matrix reservoir which receives the sample to be assayed, and at least two reaction zones into which sample fluid is drawn from the reservoir. In an embodiment containing two reaction zones, a single-point standard curve which corrects for reduced-signal effects related to loss of reagent activity and linear inhibition effects, is used to determine analyte concentration. In an embodiment containing three reaction zones, a two-point standard curve which corrects for reduced-signal effects related loss of reagent activity and non-linear inhibition effects, is used to determine analyte concentration. Also disclosed is an apparatus which uses the device for automated or semi-automated analyte assay.

Abstract: An assay device and method for determining the concentration of an analyte. Analyte introduced by liquid absorption into the matrix is used to generate H2O2, via an analyte-specific oxidase, and the H.sub.2 O.sub.2 is utilized by peroxidase in the presence of peroxidase to convert a substrate reagent to a colored reaction product. A trapping compound in the matrix competes with the substrate reagent, in the presence of the peroxidase enzyme, to produce a silent reaction product, thus proportionately reducing the amount of signal reaction product generated by a given amount of analyte. Detection of a wider range of analyte concentrations is therefore possible.