A method of detecting excessive moisture in a test strip employing moisture-sensitive reagents and including an infra-red reference dye, the method comprising: (a) measuring the reflectance of light at a first wavelength which is in the range of from 520 to 570 nm and at a second wavelength which is in the range from 700 nm to 2500 nm and at least 120 nm greater than the first wavelength and is a characteristic wavelength of the infra-red reference dye at a first predetermined time which is within 20 seconds after the moisture-sensitive reagent has been contacted with a sample containing water; (b) measuring the reflectance of light at the first wavelength and the second wavelength at a second predetermined time which is at least 40 seconds after the first measuring of the reflectance; (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: measuring the reflectance of light at a third wavelength which is in the blue region of the visible light spectrum at about 470 nm and a fourth wavelength which is in a red region of the visible light spectrum at about 625 nm; calculating a third ratio of the reflectance measurements in (f); 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; when it is determined in (f) that the primary cause is the color of the sample, determining the concentration of an analyte in the sample; and when it is determined in (f) that the primary cause is the humidity reduced sensitively of the moisture-sensitive reagent, rejecting the moisture-sensitive reagent as being humidity compromised. (a) measuring the reflectance of light at a first wavelength which is in the range of from 520 to 570 nm and at a second wavelength which is in the range from 700 nm to 2500 nm and at least 120 nm greater than the first wavelength and is a characteristic wavelength of the infra-red reference dye at a first predetermined time which is within 20 seconds after the moisture-sensitive reagent has been contacted with a sample containing water; (b) measuring the reflectance of light at the first wavelength and the second wavelength at a second predetermined time which is at least 40 seconds after the first measuring of the reflectance; (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: measuring the reflectance of light at a third wavelength which is in the blue region of the visible light spectrum at about 470 nm and a fourth wavelength which is in a red region of the visible light spectrum at about 625 nm; calculating a third ratio of the reflectance measurements in (f); 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; when it is determined in (f) that the primary cause is the color of the sample, determining the concentration of an analyte in the sample; and when it is determined in (f) that the primary cause is the humidity reduced sensitively of the moisture-sensitive reagent, rejecting the moisture-sensitive reagent as being humidity compromised. measuring the reflectance of light at a third wavelength which is in the blue region of the visible light spectrum at about 470 nm and a fourth wavelength which is in a red region of the visible light spectrum at about 625 nm; calculating a third ratio of the reflectance measurements in (f); 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; when it is determined in (f) that the primary cause is the color of the sample, determining the concentration of an analyte in the sample; and when it is determined in (f) that the primary cause is the humidity reduced sensitively of the moisture-sensitive reagent, rejecting the moisture-sensitive reagent as being humidity compromised.