title: Is heparin plasma suitable for the determination of B-type natriuretic peptide on the Beckman-Coulter Access 2?
abstract: BACKGROUND
  The use of heparin as an alternative to EDTA in the production of plasma samples is of particular interest for B-type natriuretic peptide (BNP) measurements. Lithium heparin is now widely used for the determination of biochemical parameters, including cardiac markers. The goal of this study was to determine the feasibility of measuring BNP using heparin plasma instead of EDTA plasma with the Access 2 system (Beckman-Coulter).
  
  
  METHODS
  BNP was determined in heparin plasma and EDTA plasma from 24 patients within 1 h of blood collection. Additional measurements were performed with heparin plasma, every hour for the first 4 h, and then 8 h after the collection of blood that was stored at room temperature.
  
  
  RESULTS
  At H(0), the observed BNP concentrations in heparin plasma were much higher (mean values 65% higher) than those in EDTA plasma. Using predetermined thresholds, this difference would lead to 30% discordance between samples in heparin and EDTA. BNP stability decreased over time in heparin plasma: immunoreactivity decreased approximately by 30% during the first 2 h and by 60% after 8 h.
  
  
  CONCLUSIONS
  Heparin plasma does not seem to be a suitable alternative to EDTA plasma for measurement of BNP using the Access 2 system, even if measurements are performed immediately after blood sampling.
authors.affiliation: Medical Biochemistry Laboratory, Charles Nicolle Hospital, Rouen-Cedex, France.
authors.forename: Humberto
authors.initials: H
authors.lastname: Santos
authors.forename: Bruno
authors.initials: B
authors.lastname: Cauliez
authors.forename: Christophe
authors.initials: C
authors.lastname: Tron
authors.forename: Valery
authors.initials: V
authors.lastname: Brunel
authors.forename: Alain
authors.initials: A
authors.lastname: Lavoinne
mesh_terms: D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods; D004492:Edetic Acid / Q000737:chemistry; D006493:Heparin / Q000737:chemistry*; D006801:Humans; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D055550:Protein Stability; D013696:Temperature
chemical_list: D020097:Natriuretic Peptide, Brain; D006493:Heparin; D004492:Edetic Acid