A detection method for detecting at least one analyte in at least one sample, the method comprising: a) providing at least one mobile device having at least one camera and at least one illumination source; b) providing at least one test strip having at least one test field, the test field comprising at least one test chemical for performing an optical detection reaction in the presence of the analyte; c) applying the at least one sample to the test field; d) capturing a plurality of images of at least one region of the test strip, the region comprising at least a part of the test field to which the sample is applied, comprising d1) capturing at least one image before applying the sample to the test field, with the illumination source turned off; d2) capturing at least one image before applying the sample to the test field, with the illumination source turned on; and d3) capturing at least one image after applying the sample to the test field, wherein step d3) comprises d3i) capturing at least one image with the illumination source turned off; and d3ii) capturing at least one image with the illumination source turned on e) determining a concentration of the analyte in the sample by using the images captured in step d); characterized in that, the method further comprises: f) comparing corresponding images captured in step d) with the illumination source turned on and off, and determining differences in light intensities, wherein step f) comprises f1) deriving at least one item of color information of the part of the test field to which the sample is applied for each image to be compared; f2) transforming the item of color information into at least one item of the light intensity information by using at least one camera-specific transmission function; f3) determining the differences in light intensities by using the items of light intensity information of corresponding images with the illumination source turned on and off. wherein step e) comprises using the result of step f) for determining the concentration of the analyte in the sample. a) providing at least one mobile device having at least one camera and at least one illumination source; b) providing at least one test strip having at least one test field, the test field comprising at least one test chemical for performing an optical detection reaction in the presence of the analyte; c) applying the at least one sample to the test field; d) capturing a plurality of images of at least one region of the test strip, the region comprising at least a part of the test field to which the sample is applied, comprising d1) capturing at least one image before applying the sample to the test field, with the illumination source turned off; d2) capturing at least one image before applying the sample to the test field, with the illumination source turned on; and d3) capturing at least one image after applying the sample to the test field, wherein step d3) comprises d3i) capturing at least one image with the illumination source turned off; and d3ii) capturing at least one image with the illumination source turned on d1) capturing at least one image before applying the sample to the test field, with the illumination source turned off; d2) capturing at least one image before applying the sample to the test field, with the illumination source turned on; and d3) capturing at least one image after applying the sample to the test field, wherein step d3) comprises d3i) capturing at least one image with the illumination source turned off; and d3ii) capturing at least one image with the illumination source turned on d3i) capturing at least one image with the illumination source turned off; and d3ii) capturing at least one image with the illumination source turned on e) determining a concentration of the analyte in the sample by using the images captured in step d); f) comparing corresponding images captured in step d) with the illumination source turned on and off, and determining differences in light intensities, wherein step f) comprises f1) deriving at least one item of color information of the part of the test field to which the sample is applied for each image to be compared; f2) transforming the item of color information into at least one item of the light intensity information by using at least one camera-specific transmission function; f3) determining the differences in light intensities by using the items of light intensity information of corresponding images with the illumination source turned on and off. f1) deriving at least one item of color information of the part of the test field to which the sample is applied for each image to be compared; f2) transforming the item of color information into at least one item of the light intensity information by using at least one camera-specific transmission function; f3) determining the differences in light intensities by using the items of light intensity information of corresponding images with the illumination source turned on and off. wherein step e) comprises using the result of step f) for determining the concentration of the analyte in the sample.