Evaluation of five different high-density lipoprotein cholesterol assays: the most precise are not the most accurate.
We evaluated the accuracy and performance of four different test kits for the direct determination of high-density lipoprotein (HDL)-cholesterol and compared them with the phosphotungstic acid/MgCl2 assay. All four homogeneous assays were precise (within-run CV of < 2.0% and between-run CV of < 6.4%); both assays based on immuno-inhibition had the lowest CVs (within-run 1.3% and 0.9%; between-run 2.3% and 2.2%). Interference from haemolysis was negligible, but triglyceride concentrations gave a negative interference. The effects of conjugated and unconjugated bilirubin were opposite; conjugated bilirubin showed a negative interference of up to 40%; unconjugated bilirubin interfered positively up to 50%. Using the recently validated indirect phosphotungstic acid/MgCl2 method as a comparison, all four homogeneous assays did not fulfil the National Cholesterol Education Program total error standard, mainly due to the positive biases of 12 to 42%, apparently associated with improper calibrators. Both assays involving immuno-inhibition showed a concentration-dependent bias.
de Keijzer
M H
MH
Central Clinical Chemical Laboratory, Academic Hospital Nijmegen, The Netherlands. R.deKeijzer@CKCL.AZN.NL
Elbers
D
D
Baadenhuijsen
H
H
Demacker
P N
PN
D001663:Bilirubin / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D014280:Triglycerides / Q000097:blood
D008076:Cholesterol, HDL; D006454:Hemoglobins; D011933:Reagent Kits, Diagnostic; D014280:Triglycerides; D001663:Bilirubin