title: A multicenter study on the precision and accuracy of homogeneous assays for LDL-cholesterol: comparison with a beta-quantification method using fresh serum obtained from non-diseased and diseased subjects.
abstract: BACKGROUND
  Homogeneous assays for low-density lipoprotein-cholesterol (LDL-C) have good precision and are pretreatment-free procedures. However, their accuracies have been questioned, especially in diseased subjects. In this study, we aimed to verify whether LDL-C levels determined by homogeneous assays [LDL-C (H)] agree with those determined by a beta-quantification method [LDL-C (BQ)] in fresh clinical samples.
  
  
  METHODS
  We determined LDL-C levels in 49 non-diseased and 124 diseased subjects whose triglyceride (TG) levels were less than 11.29 mmol/L (1000 mg/dL) using 12 homogeneous assays and a BQ method simultaneously.
  
  
  RESULTS
  In total, 30.6% of non-diseased subjects and 46.0% of diseased subjects were in the postprandial state. The maximum inter- and intra-assay CVs were 1.8% and 1.5%, and 8 reagents had a CV of 1.0% or less. The mean bias ranged from -0.5% to 1.8% for non-diseased subjects and from -0.7% to 1.6% for diseased subjects. For non-diseased subjects, all but one reagent achieved the National Cholesterol Education Program (NCEP) total error requirement in more than 90% of samples. However, for diseased subjects, the number of reagents that met this requirement was low. With some reagents, LDL-C (H) was higher than LDL-C (BQ), especially in subjects with hypertriglyceridemia. While for other reagents, the difference between the two methods was not associated with hypertriglyceridemia except for type I (n = 2) and type III hyperlipidemia (n = 1). Postprandial sampling was not the main factor for discordant results.
  
  
  CONCLUSIONS
  LDL-C (H) agrees with LDL-C (BQ) in non-diseased subjects, but exhibits positive bias for subjects with hypertriglyceridemia in diseased subjects for some reagents.
authors.affiliation: Department of Clinical Laboratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. tmiida@juntendo.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Miida
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Nishimura
authors.forename: Tomonori
authors.initials: T
authors.lastname: Okamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hirayama
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Ohmura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshida
authors.forename: Yoh
authors.initials: Y
authors.lastname: Miyashita
authors.forename: Masumi
authors.initials: M
authors.lastname: Ai
authors.forename: Akira
authors.initials: A
authors.lastname: Tanaka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sumino
authors.forename: Masami
authors.initials: M
authors.lastname: Murakami
authors.forename: Ikuo
authors.initials: I
authors.lastname: Inoue
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Kayamori
authors.forename: Masakazu
authors.initials: M
authors.lastname: Nakamura
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nobori
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Miyazawa
authors.forename: Tamio
authors.initials: T
authors.lastname: Teramoto
authors.forename: Shinji
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D001322:Autoanalysis / Q000592:standards; D015982:Bias; D008078:Cholesterol, LDL / Q000097:blood*; D005260:Female; D006801:Humans; D006952:Hyperlipoproteinemia Type III / Q000097:blood; D015228:Hypertriglyceridemia / Q000097:blood*; D008297:Male; D019518:Postprandial Period; D011933:Reagent Kits, Diagnostic / Q000592:standards; D014280:Triglycerides / Q000097:blood
chemical_list: D008078:Cholesterol, LDL; D011933:Reagent Kits, Diagnostic; D014280:Triglycerides