title: Analytical variability of the Fibrotest proteins.
abstract: OBJECTIVE
  The analytical variability of the Fibrotest (FT) parameters raises the issue of the test's reliability for routine use. Whereas standardization has been proposed by the International Federation of Clinical Chemistry (IFCC) for specific proteins, few data are available concerning the actual transferability of the FT proteins, i.e. haptoglobin, apolipoprotein A1 and alpha2 macroglobulin. The aim of this study was to evaluate the analytical variability of the FT proteins.
  
  
  METHODS
  During the FIBROPACA study, we evaluated 112 sera from patients with hepatitis C infection who underwent liver biopsy. We compared measurements of haptoglobin, apolipoprotein A1 and alpha2 macroglobulin by the autoanalyzers Immage (Beckman-Coulter) and the FT reference BNProspec (Dade-Behring).
  
  
  RESULTS
  Optimal concordance was found for haptoglobin (correlation: y = 1.05x -0.09; correlation coefficient = 0.98). However, apolipoprotein A1 as determined with Immage was globally 12% lower than with BNProspec (correlation: y = 0.88x -0.05; correlation coefficient = 0.91) and alpha2 macroglobulin values were 40% greater with Immage than with BNProspec (correlation: y = 1.40x -0.46; correlation coefficient = 0.96).
  
  
  CONCLUSIONS
  Inter-technique analytical variability of the Fibrotest parameters remains a major issue. After IFCC standardization of specific proteins, some discrepancies remain for alpha2 macroglobulin and, to a lesser extent, for apolipoprotein A1. National and international quality control programs would be useful to monitor analytical performance of protein assays.
authors.affiliation: Laboratoire central d'Immunologie, CHU de Nice, Hôpital de l'Archet 1, Rte de St. Antoine de Ginestière, Nice, France. allieri@unice.fr
authors.forename: Maria Alessandra
authors.initials: MA
authors.lastname: Rosenthal-Allieri
authors.forename: Marie-Line
authors.initials: ML
authors.lastname: Peritore
authors.forename: Albert
authors.initials: A
authors.lastname: Tran
authors.forename: Philippe
authors.initials: P
authors.lastname: Halfon
authors.forename: Sylvia
authors.initials: S
authors.lastname: Benzaken
authors.forename: Alain
authors.initials: A
authors.lastname: Bernard
mesh_terms: D016632:Apolipoprotein A-I / Q000097:blood*; D003951:Diagnostic Errors; D006242:Haptoglobins / Q000032:analysis*; D019698:Hepatitis C, Chronic / Q000097:blood / Q000150:complications; D006801:Humans; D008103:Liver Cirrhosis / Q000175:diagnosis*; D009391:Nephelometry and Turbidimetry / Q000592:standards; D011446:Prospective Studies; D000511:alpha-Macroglobulins / Q000032:analysis*
chemical_list: D016632:Apolipoprotein A-I; D006242:Haptoglobins; D000511:alpha-Macroglobulins