Methods of measuring analytes that include a test element quality measurement based upon intrinsic luminescence of a test chemical of the test element

A method of measuring an analyte in a fluid sample, the method comprising the steps of:

• measuring intrinsic luminescence of at least one test chemical of a test element to obtain at least one quality measurement, wherein the test element has at least one test field, the test field being an area in which at least one cohesive layer of the at least one test chemical is applied to a carrier element or is incorporated into the carrier element, wherein from at least one measured intrinsic luminescence a quality of the test chemical is related to degrading or aging of the at least one test chemical, and wherein the measuring of intrinsic luminescence of at least one test chemical is performed before a fluid sample is applied to the at least one test field of the test element;
• and
• measuring at least one analyte in an applied fluid sample to obtain an analyte measurement result, wherein at least one electrical property or at least one optical property of the at least one test chemical changeable by presence of the analyte is recorded.