The determination of HDL by quantification of HDL-cholesterol was investigated using different methods and employing the Abell method as reference. The routinely applied direct method of Huang (calibrated on Abell standardized sera) and the enzymatic method of Röschlau were tested. Results show that with the Huang method, as compared to Abell values, a total laboratory error of less than 4.5 mg/100 can be achieved in 95% of the cases. The enzymatic method gave rise to erroneous results. Comparisons between two laboratories in experiments using random and pool sera are presented.