A method for performing an analytical measurement, comprising the following steps: a) providing at least one mobile device having at least one camera; b) providing at least one test strip configured for performing a color-change detection reaction and applying at least one sample to at least one test field of the test strip, the test field containing at least one test chemical for detecting at least one analyte in the sample; c) capturing at least one image of at least a part of the test strip by using the camera, wherein said image is comprised of a plurality of pixels; d) determining at least one region of interest in the image, and associating a first sub-set of pixels with the region of interest; e) evaluating a color distribution within the first sub-set of pixels and eliminating outliers in the first sub-set of pixels; f) determining at least one sub-region of interest within the region of interest, the sub-region of interest having a smaller area than the region of interest, and associating a second sub-set of pixels with the sub-region of interest; and g) comparing at least one mean value of the color distribution of the first sub-set of pixels and at least one mean value of a color distribution of the second sub-set of pixels and determining thereby at least one item of homogeneity information on a homogeneity of the image, wherein the method further comprises at least one of the following: - comparing the number of pixels within the first sub-set of pixels with at least one threshold value, thereby determining at least one item of size sufficiency information on a sufficiency of a size of the region of interest, wherein if the at least one item of size sufficiency information indicates the region of interest being of a non-sufficient size, aborting the method for performing the analytical measurement; - comparing the number of pixels in the first sub-set of pixels before eliminating the outliers in step e) with the number of pixels in the first sub-set of pixels after eliminating the outliers in step e), wherein, if the number of pixels in the first sub-set of pixels after eliminating the outliers in step e) is smaller than a predetermined percentage of the number of pixels in the first sub-set of pixels before eliminating the outliers in step e), the method for performing the analytical measurement is aborted. a) providing at least one mobile device having at least one camera; b) providing at least one test strip configured for performing a color-change detection reaction and applying at least one sample to at least one test field of the test strip, the test field containing at least one test chemical for detecting at least one analyte in the sample; c) capturing at least one image of at least a part of the test strip by using the camera, wherein said image is comprised of a plurality of pixels; d) determining at least one region of interest in the image, and associating a first sub-set of pixels with the region of interest; e) evaluating a color distribution within the first sub-set of pixels and eliminating outliers in the first sub-set of pixels; f) determining at least one sub-region of interest within the region of interest, the sub-region of interest having a smaller area than the region of interest, and associating a second sub-set of pixels with the sub-region of interest; and g) comparing at least one mean value of the color distribution of the first sub-set of pixels and at least one mean value of a color distribution of the second sub-set of pixels and determining thereby at least one item of homogeneity information on a homogeneity of the image, - comparing the number of pixels within the first sub-set of pixels with at least one threshold value, thereby determining at least one item of size sufficiency information on a sufficiency of a size of the region of interest, wherein if the at least one item of size sufficiency information indicates the region of interest being of a non-sufficient size, aborting the method for performing the analytical measurement; - comparing the number of pixels in the first sub-set of pixels before eliminating the outliers in step e) with the number of pixels in the first sub-set of pixels after eliminating the outliers in step e), wherein, if the number of pixels in the first sub-set of pixels after eliminating the outliers in step e) is smaller than a predetermined percentage of the number of pixels in the first sub-set of pixels before eliminating the outliers in step e), the method for performing the analytical measurement is aborted.