Process for analysis of medical samples containing haemoglobin

The invention concerns a method for the determination of an analyte in a sample containing free haemoglobin in which the determination is carried out by an optical measurement and the value measured for the analyte concentration is mathematically corrected. This method is in particular suitable for determining the parameters total protein, iron and albumin in a medical sample e.g. in a serum or plasma sample. The correction of the measured value for the analyte concentration is achieved by the steps (a) measuring the blank value of the sample to be analysed, (b) measuring the blank value of a haemoglobin-free reference sample, (c) measuring the uncorrected value for the analyte concentration and (d) correcting the value obtained in step (c) by correlation with the values obtained in step (a) and (b) in order to obtain the corrected value for the analyte concentration.