Known as FibroSure in the US, is a biomarker test that uses the results of six blood serum tests to generate a score that is correlated with the degree of liver damage in people with a variety of liver diseases. FibroTest has the same prognostic value as a liver biopsy. FibroSure uses quantitative results of six serum biochemical markers, α2-macroglobulin, haptoglobin, apolipoprotein A1, bilirubin, gamma glutamyl transpeptidase (GGT), and ALT, with a patient’s age and gender to generate a measure of fibrosis and necroinflammatory activity in the liver.
FibroTest has been evaluated in relation to liver biopsy (the current reference standard in liver disease assessment) in people with hepatitis C, hepatitis B, and alcoholic liver disease. non-alcoholic fatty liver disease. They are most useful for cirrhosis and less useful for other stages of liver disease.
By 2008 it had been used in over 350,000 patients. In 2006, the French National Authority for Health recommended the use of FibroTest as one of a number of first-line assessment tool for fibrosis with untreated chronic hepatitis C.
Over 95% of tests are interpretable and allow a diagnosis of fibrosis and liver activity. In less than 5% of cases, likely false positives or false negatives are highlighted. FibroTest has been validated for chronic hepatitis C, chronic hepatitis B, chronic hepatitis C or B with HIV co-infection, alcoholic liver diseases (steatosis and steatohepatitis), and non-alcoholic steatohepatitis (diabetes, overweight, hypertriglyceridemia, hypercholesterolemia, hypertension).
FibroTest is independent of ethnic origin, sex, genotype, viral load, transaminases or the presence of comorbidities. The test has been validated in those over the age of 65 years, children, patients with renal insufficiency or renal transplanation, hemophiliacs, patients with chronic inflammatory disease, and the general population.
The tests are not applicable in 1 to 5% of cases. These cases can be detected by laboratory safety algorithms and when detected they are indicated on the results sheet:
- Acute hepatitides, e.g., acute viral hepatitis A, B, C, D, E; drug-induced hepatitis
- Extrahepatic cholestasis, e.g., pancreatic cancer, gallstones
- Severe hemolysis, e.g., some cardiac valves
- Gilbert's syndrome with high unconjugated hyperbilirubinemia
- Acute inflammatory syndrome (the blood test may be postponed)
Comparison with Liver Biopsy:
Liver biopsy is an imperfect tool; due to sampling errors, biopsy size (5 to 30 mm) and intra- and interobservor variability, it is now agreed that biopsy is an "imperfect Gold Standard " (citation required). Biopsy continues to present inconveniences: 30% of patients complain of pain, up to 3% have been noted to have complications severe enough to require hospitalization and a 0.01-0.3% rate of deaths has been reported.
There is a mean discordance of 25% between FibroTest and biopsy. Half of these discordances are attributable to an error of the biopsy, often too small, and the other half to FibroTest. The inventors report that FibroTest has comparable diagnostic and prognostic value as a 25 mm biopsy, while being noninvasive and easily repeatable.