title: Analytical and clinical performance of a detergent-based homogeneous LDL-cholesterol assay: a multicenter evaluation.
abstract: 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.
authors.affiliation: University Hospital Freiburg, Department of Clinical Chemistry, D-79106 Freiburg, Germany. manauck@med1.ukl.uni-freiburg.de
authors.forename: M
authors.initials: M
authors.lastname: Nauck
authors.forename: M S
authors.initials: MS
authors.lastname: Graziani
authors.forename: D
authors.initials: D
authors.lastname: Bruton
authors.forename: C
authors.initials: C
authors.lastname: Cobbaert
authors.forename: T G
authors.initials: TG
authors.lastname: Cole
authors.forename: F
authors.initials: F
authors.lastname: Lefevre
authors.forename: W
authors.initials: W
authors.lastname: Riesen
authors.forename: P S
authors.initials: PS
authors.lastname: Bachorik
authors.forename: N
authors.initials: N
authors.lastname: Rifai
mesh_terms: 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
chemical_list: D008078:Cholesterol, LDL; D003902:Detergents; D006454:Hemoglobins; D011933:Reagent Kits, Diagnostic; D014280:Triglycerides; D001663:Bilirubin