False negative results in the Roche assay for HDL-cholesterol.

Measurement of HDL-cholesterol is important in the risk evaluation of cardiovascular disease. Recently, we encountered a 61-year-old man with a negative result for HDL-cholesterol using the Roche assay. Further analysis revealed that this patient had a monoclonal Ig type IgMkappa, with an electrophoresis-based concentration of 55.