title: Validation of a lipoprotein(a) particle concentration assay by quantitative lipoprotein immunofixation electrophoresis.
abstract: BACKGROUND
  Low-density lipoprotein (LDL) particle (P, or molar) concentration has been shown to be a more sensitive marker of cardiovascular disease (CVD) risk than LDL cholesterol. Although elevated circulating lipoprotein(a) [Lp(a)] cholesterol and mass have been associated with CV risk, no practicable method exists to measure Lp(a)-P. We have developed a method of determining Lp(a)-P suitable for routine clinical use.
  
  
  METHODS
  Lipoprotein immunofixation electrophoresis (Lipo-IFE) involves rigidly controlled electrophoretic separation of serum lipoproteins, probing with polyclonal apolipoprotein B antibodies, then visualization after staining with a nonspecific protein stain (Acid Violet). Lipo-IFE was compared to the Lp(a) mass assay for 1086 randomly selected patient samples, and for 254 samples stratified by apo(a) isoform size.
  
  
  RESULTS
  The Lipo-IFE method was shown to be precise (CV <10% above the 50 nmol/l limit of quantitation) and linear across a 16-fold range. Lipo-IFE compared well with the mass-based Lp(a) assay (r=0.95), but was not affected by variations in apo(a) isoform size. With a throughput of 100 samples in 90 min, the assay is suitable for use in the clinical laboratory.
  
  
  CONCLUSIONS
  The Lipo-IFE method will allow Lp(a)-P to be readily tested as a CVD risk factor in large-scale clinical trials.
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Guadagno
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: Erin G
authors.initials: EG
authors.lastname: Summers Bellin
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: William S
authors.initials: WS
authors.lastname: Harris
authors.affiliation: Foundation for Health Improvement and Technology, 737 N 5th Street, Richmond, VA 23219, United States.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Dayspring
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Hoefner
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: Dawn L
authors.initials: DL
authors.lastname: Thiselton
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: Brant
authors.initials: B
authors.lastname: Stanovick
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States.
authors.forename: G Russell
authors.initials: GR
authors.lastname: Warnick
authors.affiliation: Health Diagnostic Laboratory, Inc., 737 N. 5th Street, Richmond, VA 23219, United States. Electronic address: jmcconnell@hdlabinc.com.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: McConnell
mesh_terms: D006801:Humans; D007122:Immunoelectrophoresis / Q000379:methods* / Q000592:standards*; D017270:Lipoprotein(a) / Q000097:blood*
chemical_list: D017270:Lipoprotein(a)
keywords: Apo(a) isoform size; Cholesterol; Electrophoresis; Immunofixation; Lipoprotein particles; Lipoprotein(a)