Abstract: Oxygen-independent methods, systems and devices for the enzymatic colorimetric assay and detection of biochemical analytes. Two systems are described, both of which produce less than one equivalent of dye per equivalent of substrate, maintaining dye concentrations in the range where Beer's law predicts a linear color-concentration relationship. One system produces an analog color signal from an analog analyte input, the other system produces a digital color signal from an analog analyte input.

Abstract: The invention provides a reagent system for the enzymatic determination of an oxidizable substrate in a fluid sample; the system includes an active amine trap for inactivating high concentrations of aldehyde and ketone oxidation products comprising a combination of at least one primary amine and at least one alpha-effect amine. An example of the oxidizable substrate is alcohol.

Abstract: A system for quantitative colorimetric analysis of biological fluids or organic compounds, including NAD(P)H, or a substrate of an enzyme which reacts with the formation or consumption of NAD(P)H. Concentrations of organic substrates for example alcohol, cholesterol, uric acid, in a biological fluid such as saliva, blood or urine may be determined. The system gives a digital reading of the organic material the concentration which is sought to be determined; the concentration of NAD(P)H is determined by a color change or color "signal" when the NAD(P)H is above a threshold concentration and by the absence of a color signal when the concentration of NAD(P)H is below the threshold concentration. The system includes a chromogen, an electron-accepting reactant which, until exhausted, prevents a visible color change due to accumulation of reduced chromogen, and a catalyst.

Abstract: An assay system useful for the determination of NAD(P)H, NAD(P), or a substrate of an enzyme which reacts with the formation or comsumption of NAD(P)H. Concentrations of organic substrates for example alcohol, cholesterol, uric acid, in a biological fluid such as saliva, blood or urine may be determined. The system includes a diaphorase which catalyzes a NAD(P)H-dependent reduction of a chromogen to cause a visible color change; this color change is indicative of the concentration sought to be determined. The system includes a chromogen which is a first substrate for the diaphorase which causes a color change when reduced by NAD(P)H, and a second substrate which is a competing substrate for the diaphorase; the competing substrate is irreversibly reduced by the diaphorase. The system is capable of measuring colorimetrically without dilution concentrations of organic compounds in biological fluids which previously could not be measured in such concentration.