Patent ID: 8611619

Claim:
A method for detecting the presence and/or amount of an analyte in a sample by obtaining a reliable read-out from a composite signal represented by a coloured area on a test member, the colour being obtained as a response to the analyte, the method comprising: providing as said test member a read-out substrate in the form of a bibulous strip having at least one response area and at least one marker on said response area, the marker causing a colour change when the analyte in the sample undergoes a reaction; applying a liquid sample, blood, plasma, or any other suitable liquid containing an analyte, on said strip, whereby said sample is caused to migrate by capillary forces along the strip, and undergoes a reaction at predefined locations on said strip; illuminating the assay strip; recording an image of said strip; calculating a colour saturation value S for said image using said at least two wavelength ranges; the S-value being calculated as S = MAX - MIN MAX = 1 - MIN MAX using the “Hue, Saturation, Value” (HSV) system; wherein MAX is the largest value for the intensity of the at least two registered wavelengths, and MIN is the smallest; and using the S-value for determining a result of the assay by comparing the S-values with a selected threshold value G, and correlating the S-value to a physical quantity.