Validation of homogeneous assays for HDL-cholesterol using fresh samples from healthy and diseased subjects

Background: High-density lipoprotein-cholesterol (HDL-C) is a negative risk factor for cardiovascular events. Although several homogeneous HDL-C assays are available, their accuracy has not been validated, particularly in subjects with disease. We aimed to clarify whether HDL-C concentrations measured by homogeneous assays [HDL-C (H)] agree with those determined by the reference measurement procedures [HDL-C (RMP)] using ultracentrifugation and precipitation with heparin-manganese reagent in fresh clinical samples. Methods: HDL-C concentrations in samples from 48 healthy subjects and 119 subjects with disease were determined using 12 homogeneous assays and RMPs. Results: All reagents showed excellent intra- and inter-assay CVs (<2.23%) for two pooled sera. Furthermore, the mean bias was within ±1.0% in nine reagents using samples from healthy subjects and in eight reagents using samples from subjects with disease. In a single HDL-C (H) determination, the total error requirement of the National Cholesterol Education Program (95% of results<13%) was fulfilled in nine reagents using samples from healthy subjects and six reagents in those from subjects with disease. Error component analysis revealed that only one reagent exceeded ±10% total error in samples from healthy subjects, whereas four reagents exceeded this error in samples from subjects with disease. Correlations between HDL-C (H) and HDL-C (RMP) revealed that the slopes were within 1.00±0.06 in six reagents in healthy subjects, and eight reagents in subjects with disease. Conclusions: Except for three reagents, HDL-C (H) agrees well with HDL-C (RMP) in subjects with common disease, but not in those with extremely low HDL-C or abnormal HDL composition.