title: Comparison of four direct homogeneous methods for the measurement of low-density lipoprotein cholesterol.
abstract: BACKGROUND
  The primary lipoprotein risk factor is low-density lipoprotein cholesterol (LDL-C), and medication is targeted at lowering LDL-C values. To clarify the usefulness of direct homogeneous assays for LDL-C measurement, we compared the values obtained by various reagents to those obtained by the Friedewald equation and analyzed different reactivity to IDL/VLDL and LDL.
  
  
  METHODS
  Serum samples were collected from 55 patients with hypercholesterolemia. The LDL-C concentrations were determined by four direct homogeneous assays using reagent A (Kyowa Medex), B (Sekisui Medical), C (Denka Seiken), and D (Sysmex), which are commercially available.
  
  
  RESULTS
  Significant correlation was observed in LDL-C values obtained by the homogeneous assays and the Friedewald equation. However, there were two discrepancies in reagents B and C, respectively. These assays showed 40% and 55% lower LDL-C values than those calculated by the Friedewald equation, respectively. Reactivity to the IDL fraction in reagents B and C was lower than in reagents A and D.
  
  
  CONCLUSIONS
  Direct homogeneous assays for LDL-C are suitable for routine laboratory examination. However, it was shown that attention should be given to the different reactivity to IDL and LDL among reagents in some clinical samples.
authors.affiliation: Division of Laboratory Diagnosis, Sapporo Medical University Hospital, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamada
authors.forename: Naoki
authors.initials: N
authors.lastname: Tsuji
authors.forename: Tomoko
authors.initials: T
authors.lastname: Fujita
authors.forename: Maki
authors.initials: M
authors.lastname: Tanaka
authors.forename: Kageaki
authors.initials: K
authors.lastname: Kuribayashi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Watanabe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001774:Blood Chemical Analysis; D002648:Child; D008078:Cholesterol, LDL / Q000097:blood*; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000175:diagnosis*; D006951:Hyperlipoproteinemias / Q000097:blood / Q000175:diagnosis*; D008875:Middle Aged; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D008078:Cholesterol, LDL