Analytical and clinical performance of a detergent-based homogeneous LDL-cholesterol assay: a multicenter evaluation.
BACKGROUND
LDL-cholesterol (LDL-C) concentrations currently are determined in most clinical laboratories using the Friedewald calculation. This approach has several limitations and may not always meet the current total error recommendation in LDL-C measurement of </=12% established by the National Cholesterol Education Program.


METHODS
In a multicenter study, we evaluated the analytical and clinical performance of a homogeneous LDL-C assay (LDL-C(Roche); Roche Diagnostics, Indianapolis, IN) in a comparison with a beta-quantification method.


RESULTS
This direct assay correlated highly with a beta-quantification method (r = 0.968; y = 1.037x - 95.8 mg/L; n = 355; 95% confidence intervals, 1.011-1.063 for the slope and -129.5 to 62.0 mg/L for the y-intercept) and met the current total error requirement. The assay was not affected significantly by concentrations of hemoglobin up to 6000 mg/L or bilirubin up to 500 mg/L. However, a negative bias of 10% was seen when triglyceride concentrations exceeded 10 000 mg/L. At the medical decision cut-point range, the LDL-C(Roche) assay showed positive predictive values of 91-100% and negative predictive values of 80-99%. Furthermore, the clinical utility of the assay seemed unaffected in samples obtained postprandially.


CONCLUSIONS
The homogeneous LDL-C(Roche) assay meets the currently established analytical performance goals and may be useful for the diagnosis and management of hyperlipidemic patients.
Nauck
M
M
University Hospital Freiburg, Department of Clinical Chemistry, D-79106 Freiburg, Germany. manauck@med1.ukl.uni-freiburg.de
Graziani
M S
MS
Bruton
D
D
Cobbaert
C
C
Cole
T G
TG
Lefevre
F
F
Riesen
W
W
Bachorik
P S
PS
Rifai
N
N
D001663:Bilirubin / Q000032:analysis; D008078:Cholesterol, LDL / Q000097:blood*; D003902:Detergents; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D019518:Postprandial Period; D011933:Reagent Kits, Diagnostic; D012044:Regression Analysis; D014280:Triglycerides / Q000097:blood
D008078:Cholesterol, LDL; D003902:Detergents; D006454:Hemoglobins; D011933:Reagent Kits, Diagnostic; D014280:Triglycerides; D001663:Bilirubin