Miles Inc.

Lloyd A Schick

Meitak Teresa Yip

James P Albarella

A new and improved test device and method of determining the presence or concentration of a predetermined analyte, such as glucose, cholesterol or occult blood, in a test sample are disclosed. The test device includes a test pad comprising a suitable carrier matrix incorporating an indicator reagent composition capable of interacting with the predetermined analyte to produce a detectable or measurable response. In addition, the new and improved indicator reagent composition, comprising an indicator dye, such as a redox indicator, like a benzidine indicator; a redox mediator, such as an oxidase enzyme capable of interacting with the predetermined analyte and a peroxidase enzyme; a metal ion complex; and a cooxidant selected from the group consisting of bromate ion, chlorate ion, perchlorate ion, chromate ion, an organic oxidant like a peroxide, a hydroperoxide or a N-halo compound, and combinations thereof, is incorporated into the carrier matrix to provide a more accurate, ascorbate interference-resistant assay of a test sample for the predetermined analyte.

Ascorbate interference-resistant composition, device and method of

The present invention is directed to the elimination of ascorbic acid interference in assay systems, particularly assay systems based upon oxidase-peroxidase coupled reactions. When ascorbic acid is present in a sample, it can act as a reductant thereby interfering with an assay's reagent system. The present invention eliminates this inteference by quickly oxidizing any ascorbate thereby preventing ascorbate from acting as an unwanted reductant. The ascorbate is oxidized using a dual oxidant system comprising a water soluble polymer bound to Cu.sup.+2 and an organic or inorganic oxidant such as chromate, peroxide, or a N-halo derivative. This invention is surprisingly selective and generally will not itself interfere with the assay's reagent system. Furthermore, the present invention is so fast and efficient that it can be incorporated into a convenient format, such as a conventional 'dip-and-read' reagent test strip system.

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Bristol, IN, United States of America

Lloyd A Schick