Platelet count | |
unit | 10^9/L 10^3/mm^3 |
gammaglutamyl transferase (U/L) | |
Age (years) | |
Cholesterol | |
unit | mg/dL mmol/L |
Liver biopsy is currently considered the best test for staging hepatic fibrosis. Unfortunately, liver biopsy carries a small but significant risk, and is an invasive and potentially painful procedure.
Having noninvasive means to assess hepatic fibrosis is desirable.
In patients with Hepatitis C (HCV), hepatic fibrosis stage relates to prognosis, guides management decisions, and monitoring of disease.
Forns et al. developed a noninvasive index derived from age, gammaglutamyl transferase (GGT), cholesterol, and platelet count in a study of 476 untreated HCV patients.
The formula developed is:
Note: The Forns Index gives prediction score according to F2-F4 of the Scheuer classification from the Scheuer fibrosis score system. The diagnostic accuracy of this index has been confirmed in patients with HIV-HCV coinfection.
Interpretation:
Cut off Score | Description | PPV (%) | NPV (%) |
---|---|---|---|
<=4.2 | Exclude significant fibrosis | 40 | 96 |
>=6.9 | Diagnosis of significant fibrosis. | 66 | 80 |
4.3-6.8 | Indeterminate | x | x |
* PPV: Positive Predictive Value
* NPV: Negative Predictive Value
Reference: