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Comp Hepatol
2002 Dec 30;1(1):3
A prospective
assessment of the inter-laboratory variability of biochemical
markers of fibrosis (FibroTest.jpg) and activity (ActiTest) in patients
with chronic liver disease.
Halfon P, Imbert-Bismut F, Messous
D, Antoniotti G, Benchetrit D, Cart-Lamy P, Delaporte G, Doutheau
D, Klump T, Sala M, Thibaud D, Trepo E, Thabut D, Myers RP, Poynard
T.
Service d'Hepato-Gastroenterologie, Groupe Hospitalier Pitie-Salpetriere,
AP-HP, Universite Paris 6 et UPRESA 8067 CNRS Paris, 47 Boulevard
de l'Hopital, 75651 Paris Cedex 13, France. tpoynard@teaser.fr
BACKGROUND: Biochemical markers for liver fibrosis (FibroTest.jpg)
and necroinflammatory features (ActiTest) are an alternative
to liver biopsy in patients with chronic hepatitis C. Our aim
was to assess the inter-laboratory variability of these tests,
and their 6 components (gamma-glutamyl transpeptidase, alanine
aminotransferase, alpha2-macroglobulin, haptoglobin, apolipoprotein
A1, and total bilirubin) and to identify factors associated with
this variability.
RESULTS: Serum of 24 patients
with chronic hepatitis C or severe alcoholic liver disease were
prospectively recorded and analyzed in one reference center and
in 8 additional laboratories. When gamma-glutamyl transpeptidase
and alanine aminotransferase were expressed in international
units, there was no significant difference between laboratories
in the results of FibroTest.jpg or ActiTest; kappa statistics were
greater than 0.50 with only 0.8% of cases (3/384) with a discordance
of more than one stage. The main factor significantly associated
with variability was the expression of gamma-glutamyl transpeptidase
and alanine aminotransferase, as multiples of upper limit of
reference values. The use of standardized method with pyridoxal
phosphate reduced the variability of alanine aminotransferase
expression, and standardized original Szasz method reduced the
variability of gamma-glutamyl transpeptidase expression.
CONCLUSIONS: The variability
of FibroTest.jpg and ActiTest was acceptable without clinical consequences
for the prediction of the stage of liver fibrosis and grade of
activity. Standardized methods and assay calibration should be
used and expression of alanine aminotransferase and gamma-glutamyl
transpeptidase in multiples of the upper limit of reference values
should not be employed.
