A method, a mobile device (112) and a kit (148) for performing an analytical measurement are disclosed, wherein outliers are eliminated. The method comprises: providing at least one mobile device (112) having at least one camera (114)； providing at least one test strip (118) configured for performing a color-change detection reaction and applying at least one sample to at least one test field (120) of the test strip (118), the test field (120) containing at least one test chemical for detecting at least one analyte in the sample； capturing at least one image (124) of at least a part of the test strip (118) by using the camera (114), wherein said image (124) is comprised of a plurality of pixels； determining at least one region of interest (128) in the image (124), and associating a first sub-set of pixels with the region of interest (128)； evaluating a color distribution within the first sub- set of pixels and eliminating outliers in the first sub-set of pixels； determining at least one sub-region of interest (134) within the region of interest (128), the sub-region of interest (134) having a smaller area than the region of interest (128), and associating a second sub- set of pixels with the sub-region of interest (134)； and 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 (124).
