Abstract: A method for improving the accuracy of temperature sensitive diagnostic assays which are carried out using reflectance spectrometers to detect color changes in a solid test system which has been contacted with a fluid test system suspected of containing an analyte whose presence and/or concentration is being sought. The method involves determining the temperature of the solid test material by measuring the reflectance of a thermochromic liquid crystal in close proximity to the solid test material and correcting the result of the assay for a change in temperature from a pre-selected nominal temperature.

Abstract: A method, composition and test device for determining the ionic strength or specific gravity of a test sample are disclosed. The method utilizes a test device comprising a test pad, wherein the test pad includes a carrier matrix incorporating a reagent composition capable of producing a detectable and measurable response that correlates to the ionic strength and the buffer capacity, and therefore the specific gravity, of the test sample. The reagent composition, comprising a strong polyelectrolyte, an indicator comprising: (i) a dye that is metachromatic and sensitive to pH changes, or (ii) or a combination of metachromatic dye and a pH indicator dye, in a suitable carrier, and buffered at a pH of 3 or less, is incorporated into a carrier matrix to provide a test pad of a device useful in an ionic strength or specific gravity assay of a test sample.

Abstract: A composition, method and test device for determining the divalent cation concentration or estimating the specific gravity of a test sample are disclosed. The method utilizes a test device comprising a test pad, wherein the test pad includes a carrier matrix incorporating a reagent composition capable of interacting with divalent cations present in the test sample to produce a detectable and measurable response that correlates to the divalent cation concentration or to the specific gravity of the test sample. The reagent composition, comprising a metal-sensitive triphenylmethane dye; a buffer; an optional chelating agent; and suitable carrier, is incorporated into a carrier matrix to provide a test pad of a device useful in a divalent cation assay or a specific gravity assay of a test sample.