title: Intra-laboratory analytical variability of biochemical markers of fibrosis (Fibrotest) and activity (Actitest) and reference ranges in healthy blood donors.
abstract: Combinations of tests comprising alpha2-macroglobulin, haptoglobin, apolipoprotein Al, gamma-glutamyltransferase, total bilirubin (Fibrotest) and alanine aminotransferase (Actitest) are being developed as alternatives to liver biopsy in patients with chronic hepatitis C. The aim of this study was to assess in the same laboratory the impact of parameter assay variations on Fibrotest and Actitest results and intra-patient reproducibility of the two tests. The stability of the samples for each test was studied after storage at -80 degrees C and -20 degrees C. Within-run, between-run and total imprecision for each parameter assay, and for Fibrotest and Actitest results, were determined. Transferability of assay results between different analyzers was studied. Intra-patient reproducibility was assessed in 55 hospitalized patients. Fibrotest and Actitest reference ranges were determined in 300 blood donors (reference group). The stability of the parameters was affected by serum storage at -20 degrees C only. The impact of parameter analytical variability on Fibrotest and Actitest results was less than 10% and intra-patient reproducibility was acceptable (p > 0.05). The transferability between different analyzers of results of assays performed under the same standardized and calibration conditions was excellent. Fibrotest and Actitest reference ranges in blood donors were (mean+/-SE) 0.075+/-0.004 and 0.068+/-0.004, respectively. The low intra-laboratory and intra-patient variability in Fibrotest and Actitest results confirm Fibrotest and Actitest reliability.
authors.affiliation: Service of Biochemistry, Hôpital La Pitie-Salpétrière, Paris, France. Fimbis@aol.com
authors.forename: Françoise
authors.initials: F
authors.lastname: Imbert-Bismut
authors.forename: Djamila
authors.initials: D
authors.lastname: Messous
authors.forename: Vincent
authors.initials: V
authors.lastname: Thibault
authors.forename: Vincent
authors.initials: V
authors.lastname: Thibaut
authors.forename: Rob B
authors.initials: RB
authors.lastname: Myers
authors.forename: Annie
authors.initials: A
authors.lastname: Piton
authors.forename: Dominique
authors.initials: D
authors.lastname: Thabut
authors.forename: Laure
authors.initials: L
authors.lastname: Devers
authors.forename: Bernard
authors.initials: B
authors.lastname: Hainque
authors.forename: Anne
authors.initials: A
authors.lastname: Mercadier
authors.forename: Thierry
authors.initials: T
authors.lastname: Poynard
mesh_terms: D000367:Age Factors; D000410:Alanine Transaminase / Q000097:blood; D000704:Analysis of Variance; D016632:Apolipoprotein A-I / Q000097:blood / Q000737:chemistry; D001663:Bilirubin / Q000097:blood / Q000737:chemistry; D015415:Biomarkers / Q000097:blood; D001782:Blood Donors; D015992:Body Mass Index; D019963:Clinical Chemistry Tests / Q000295:instrumentation / Q000592:standards / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D003955:Diagnostic Tests, Routine / Q000295:instrumentation / Q000592:standards / Q000706:statistics & numerical data; D004795:Enzyme Stability; D005355:Fibrosis; D005615:Freezing; D006242:Haptoglobins / Q000032:analysis / Q000737:chemistry; D019698:Hepatitis C, Chronic / Q000097:blood*; D006801:Humans; D012016:Reference Values; D015203:Reproducibility of Results; D012737:Sex Factors; D013696:Temperature; D000511:alpha-Macroglobulins / Q000032:analysis / Q000737:chemistry; D005723:gamma-Glutamyltransferase / Q000097:blood / Q000737:chemistry
chemical_list: D016632:Apolipoprotein A-I; D015415:Biomarkers; D006242:Haptoglobins; D000511:alpha-Macroglobulins; D005723:gamma-Glutamyltransferase; D000410:Alanine Transaminase; D001663:Bilirubin