Test element for detecting an analyte in a sample

A device for detecting at least one metabolite or other analyte in a body fluid or other sample, the device comprising:

• a test element comprising:
• at least one test field having a test field surface for applying the sample, wherein the test field comprises at least one detection reagent which is set up to carry out at least one detectable reaction in the presence of the analyte, wherein the detection reaction is an optically detectable reaction and is set up such that at least one detection substance is formed in the detectable reaction;
• at least one distributor element, wherein the distributor element has at least one distributor surface facing the test field surface, wherein at least one capillary gap is formed between the distributor surface and the test field surface, wherein the capillary gap has a gap width, wherein the capillary gap is set up such that a layer of the sample having a layer thickness of no more than 50 μm can form within the capillary gap, wherein the test field comprises a test field material, wherein the test field material has a surface roughness of less than 50 μm;
• and
• at least one calibration device, wherein the calibration device is set up to determine directly and/or indirectly the detection substance in the sample outside the test field and wherein the device is further set up to carry out the detection of the analyte taking account of said determination of the detection substance in the sample outside the test field.