title: Evaluating the accuracy and increasing the reliable diagnosis rate of blood tests for liver fibrosis in chronic hepatitis C.
abstract: BACKGROUND
  The reliable diagnosis rate of diagnostic tests is provided by their intervals with acceptable accuracy (e.g. >/=90%) where a liver biopsy can be avoided.
  
  
  OBJECTIVE
  To evaluate the overall accuracy and improve the reliable diagnosis rates of blood tests for significant liver fibrosis.
  
  
  METHODS
  Five blood tests were compared with Metavir fibrosis (F) staging in 1056 patients with chronic hepatitis C.
  
  
  RESULTS
  Area under the receiver operating characteristics (F0-1 vs. F2-4) were: FibroMeter: 0.853, Fibrotest: 0.811, Fib-4: 0.799, aspartate aminotransferase to platelet ratio index (APRI): 0.786 and Hepascore: 0.784 (P<10(-3) between tests). The reliable diagnosis rates based on two traditional intervals defined by thresholds >/=90% of negative predictive values (NPV) and positive predictive values (PPV), diagnosing F0/1 and F2/3/4, respectively, were: FibroMeter: 43.5%, APRI: 19.6%, Fibrotest: 17.1%, Hepascore: 3.9%, Fib-4: 1.7% (P<10(-3)). By dividing the indeterminate interval by the diagnostic cut-off, two new intervals could be diagnosed reliably: F1/2 and F1/2/3. Accordingly, the reliable diagnosis rate was increased, e.g. FibroMeter: 75.5% (accuracy: 89.5%) with three intervals (F0/1, F1/2, F2/3/4). It was possible to further increase this rate by using the more exportable 90% sensitivity/specificity thresholds, e.g. FibroMeter: 90.2% (accuracy: 86.4%). By using the four intervals, the reliable diagnosis rate was 100% (accuracy: 89.5% with predictive value (PV) and 87.5% with sensitivity/specificity).
  
  
  CONCLUSIONS
  Reliable diagnosis is a diagnostic index devoted to clinical practice. Its rate can be increased by creating new intervals between diagnostic cut-off and 90% PVs or sensitivity/specificity thresholds. This increased the overall accuracy from 78.1 to 89.5% and reduced the need for a liver biopsy from 56.5 to 0% with the most accurate test.
authors.affiliation: Service d'Hépato-gastroentérologie et laboratoire HIFIH, IFR 132, CHU, Angers, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Calès
authors.forename: Victor
authors.initials: V
authors.lastname: de Ledinghen
authors.forename: Philippe
authors.initials: P
authors.lastname: Halfon
authors.forename: Yannick
authors.initials: Y
authors.lastname: Bacq
authors.forename: Vincent
authors.initials: V
authors.lastname: Leroy
authors.forename: Jérôme
authors.initials: J
authors.lastname: Boursier
authors.forename: Juliette
authors.initials: J
authors.lastname: Foucher
authors.forename: Marc
authors.initials: M
authors.lastname: Bourlière
authors.forename: Anne
authors.initials: A
authors.lastname: de Muret
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sturm
authors.forename: Gilles
authors.initials: G
authors.lastname: Hunault
authors.forename: Frédéric
authors.initials: F
authors.lastname: Oberti
mesh_terms: D000328:Adult; D001706:Biopsy; D005260:Female; D006403:Hematologic Tests / Q000592:standards*; D019698:Hepatitis C, Chronic / Q000150:complications*; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity