A process for analysing a medical sample, especially of a bodily fluid, using an analysing device, in which a test fluid containing an aliquot part of the sample and reagents is in a cell and the temperature of the test fluid in the cell is determined. In order to determine the temperature of the test fluid contactlessly and directly, the optical absorption of a calibration fluid is determined in a temperature calibration stage at at least two wavelengths in the near i/r range at various temperatures in order to obtain a set of calibration data concerning the temperature dependence of the optical absorption and in a temperature measurement stage the optical absorption of a test fluid of unknown temperature is measured at the same wavelengths and its temperature found by comparison with the absorption data obtained in the measurement stage.
