A method for calibration and/or error detection in an optical measurement device for biological samples having at least a first and a second measurement channel is described. The method comprises calculating an updated reference factor for the second measurement channel based on the first and second detection signals, comparing the updated reference factor with at least one current reference factors and depending on the result of the comparison, storing the updated reference factor as a current reference factor for use in a later measurement in the second measurement channel or keeping the current reference factors for use in a later measurement in the second measurement channel.