Diagnostics based on tetrazolium compounds
AssigneeLifeScan, Inc.
InventorsTianmei Ouyang, Yeung Siu Yu
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Abstract
A reagent is suitable for measuring the concentration of an analyte in a hemoglobin-containing biological fluid, such as whole blood. The reagent comprises dehydrogenase enzyme that has specificity for the analyte, NAD, an NAD derivative, pyrrolo-quinoline quinone (PQQ), or a PQQ derivative, a tetrazolium dye precursor, a diaphorase enzyme or an analog thereof, and a nitrite salt. The reagent causes dye formation that is a measure of the analyte concentration. The nitrite salt suppresses interfering dye formation caused non-enzymatically by the hemoglobin. Preferably, the reagent is used in a dry strip for measuring ketone bodies, such as beta-hydroxybutyrate.
Claims14
A reagent for measuring a concentration of an analyte in a hemoglobin-containing biological fluid, comprising
- a) a dehydrogenase enzyme that has specificity for the analyte,
- b) pyrrolo-quinoline quinone(PQQ), or a PQQ derivative
- c) a tetrazolium dye precursor,
- d) a diaphorase enzyme or an analog thereof, and
- e) a nitrite salt.
A dry reagent test strip for determining the presence and amount of an analyte in a hemoglobin-containing biological fluid, comprising
- a) a support layer,
- b) on the support layer, a test pad having a coating that comprises
- i) a dehydrogenase enzyme that has specificity for the analyte,
- ii) pyrrolo-quinoline quinone (PQQ), or a PQQ derivative
- iii) a tetrazolium dye precursor, and
- iv) a diaphorase enzyme or an analog thereof, and
- c) on the test pad, a bibulous top layer that is coated with a nitrite salt.
Dependencies are inferred from the claim text.