Device and method for detection of humidity-compromised urine test strips

摘要

The timing of the reaction of moisture-sensitive reagents for detecting the presence of analytes, e.g. leukocytes in urine samples, is used to detect when the reagents have been compromised by excess humidity. The ratio of light reflectance at wavelengths characteristic of the products of reaction between the reagents and the analyte and an infra-red reference dye is measured at two preset times after a urine sample has been applied to a test strip and used to determine whether the reagents have been compromised by excessive humidity. The presence of unusually dark samples is determined from the reflected light at 470 and 625 nm in order to confirm that the test strips are humidity-compromised.

主权项

1. A method of analyzing a moisture-sensitive reagent disposed on a substrate and contacted with a sample containing water, the method comprising:
(a) measuring the reflectance of light at a first wavelength and a second wavelength at a first predetermined time after contacting said reagent with said sample; (b) measuring the reflectance of light at the first wavelength and the second wavelength at a second predetermined time after contacting said reagent with said sample, the second predetermined time being after the first predetermined time; (c) calculating a first ratio of the reflectance measurements in (a) and a second ratio of the reflectance measurements in (b); (d) determining a level of activity of the reagent between the first and the second predetermined times by comparing the first ratio and the second ratio calculated in (c); (e) when the level of activity of the reagent determined in (d) is at or above an expected level, determining a concentration of an analyte in the sample; and (f) when the level of activity of the reagent determined in (d) is less than the expected level:
(1) measuring the reflectance of light at a third wavelength in a blue region of a visible light spectrum and a fourth wavelength in a red region of the visible light spectrum at a third predetermined time;(2) calculating a third ratio of the reflectance measurements in (f)(1);(3) based on the third ratio, determining whether a primary cause of the less than expected activity is due to a color of the sample or a humidity reduced sensitively of the moisture-sensitive reagent;(4) when it is determined in (f)(3) that the primary cause is the color of the sample, determining the concentration of an analyte in the sample; and(5) when it is determined in (f)(3) that the primary cause is the humidity reduced sensitively of the moisture-sensitive reagent, rejecting the moisture-sensitive reagent as being humidity compromised.