초록 ▼

A chemical timer for a direct-reading reagent test strip changes color a predetermined time after a biological fluid is applied to the strip. The strip measures the concentration of an analyte in the fluid. The timer is a dry coating of an indicator, an enzyme-containing reagent that when hydrated c

A chemical timer for a direct-reading reagent test strip changes color a predetermined time after a biological fluid is applied to the strip. The strip measures the concentration of an analyte in the fluid. The timer is a dry coating of an indicator, an enzyme-containing reagent that when hydrated can react with glucose to change the color of the indicator, an inhibitor to inhibit the change in color of the indicator, glucose, and optionally, an aldose that does not react with the enzyme in the reagent. Preferably, the reagent and glucose are present in excess in the coating, and the time it takes for the timer color to change can be controlled by the inhibitor concentration. The aldose provides timer stability, probably by interfering with glycosylation by the glucose in the dry state.

대표청구항 ▼

[ We claim:] [1.] A chemical timer for a visual-reading reagent test strip for measuring the concentration of glucose in a biological fluid that is applied to the strip, the timer comprising a dry coating ofa) a colored indicator composition,b) a reagent that, when hydrated, reacts with glucose to c

[ We claim:] [1.] A chemical timer for a visual-reading reagent test strip for measuring the concentration of glucose in a biological fluid that is applied to the strip, the timer comprising a dry coating ofa) a colored indicator composition,b) a reagent that, when hydrated, reacts with glucose to change the color of the indicator,c) an inhibitor to inhibit the change in color of the indicator, andd) glucose, which the inhibitor and glucose concentrations in the dry coating are selected so that the glucose, over a predetermined time after the biological fluid is applied to the strip, reacts with the reagent to change the color of the indicator.