Analytical apparatus for detecting at least one analyte in a sample, in particular for detecting blood glucose, - wherein the analytical apparatus contains at least one test element, the test element containing at least one test chemical, the test element having at least one test field, the test field being an area in which at least one coherent layer of the test chemical is applied to a carrier element or incorporated into a carrier element, the analytical apparatus being equipped, by means of the test element, to carry out at least one analyte measurement, wherein the test chemical is a substance or a substance mixture, which is equipped, in presence of the analyte, to change at least one detectable changeable property, in particular an electrical and/or optical property, wherein in the analyte measurement the at least one property changeable by presence of the analyte of the at least one test chemical of the test element is recorded, and - wherein the analytical apparatus is furthermore equipped to carry out at least one quality measurement on the test chemical, wherein in the quality measurement at least an intrinsic luminescence of the test chemical is recorded and from the intrinsic luminescence a quality of the test chemical is concluded, wherein the quality of the test chemical is information which provides information about a state of the test chemical, wherein the quality comprises at least one item of quality information which quantifies a degradation or an aging state of the test chemical, the analytical apparatus being equipped to carry out the quality measurement at least once before the analyte measurement, the analytical apparatus being equipped, corresponding to the recorded quality, to carry out at least one action, selected from the group consisting of: an output of a message to a user, in particular a warning message; a dissemination of at least one item of information about the quality to at least a further device; a storage of at least one item of information about the quality in a data store; a prevention or facilitation of the analyte measurement; a consideration or non-consideration of an analyte measurement already carried out; a calculation of a concentration of the analyte in the sample from the recorded property, taking into consideration the quality of the test chemical, in particular using a correction taking into consideration the quality. - wherein the analytical apparatus contains at least one test element, the test element containing at least one test chemical, the test element having at least one test field, the test field being an area in which at least one coherent layer of the test chemical is applied to a carrier element or incorporated into a carrier element, the analytical apparatus being equipped, by means of the test element, to carry out at least one analyte measurement, wherein the test chemical is a substance or a substance mixture, which is equipped, in presence of the analyte, to change at least one detectable changeable property, in particular an electrical and/or optical property, wherein in the analyte measurement the at least one property changeable by presence of the analyte of the at least one test chemical of the test element is recorded, and - wherein the analytical apparatus is furthermore equipped to carry out at least one quality measurement on the test chemical, wherein in the quality measurement at least an intrinsic luminescence of the test chemical is recorded and from the intrinsic luminescence a quality of the test chemical is concluded, wherein the quality of the test chemical is information which provides information about a state of the test chemical, wherein the quality comprises at least one item of quality information which quantifies a degradation or an aging state of the test chemical,