What a Liver Profile and NASH/FibroSure Assess
A liver profile provides basic hepatic biochemistry (transaminases, bilirubin, albumin, platelets), while FibroSure (FibroTest) is a proprietary blood-based biomarker that specifically assesses the degree of liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) and can help identify those with non-alcoholic steatohepatitis (NASH).
Liver Profile Components and Purpose
A standard liver profile typically includes:
- Transaminases (AST, ALT): Markers of hepatocyte injury
- Alkaline phosphatase and bilirubin: Indicators of cholestasis
- Albumin and prothrombin time: Measures of synthetic liver function
- Platelet count: Can indicate portal hypertension and advanced fibrosis
These basic tests help identify liver injury but cannot accurately stage fibrosis or diagnose NASH on their own. They serve as the foundation for calculating simple non-invasive fibrosis scores like FIB-4 (using age, AST, ALT, and platelets) 1.
FibroSure (FibroTest) Specifics
FibroSure is the U.S. commercial name for FibroTest, a patented serum biomarker panel that assesses liver fibrosis severity 1.
What FibroSure Measures:
- Primary target: Hepatic fibrosis stage (F0-F4)
- Specific focus: Detection of advanced fibrosis (stages F3-F4, including bridging fibrosis and cirrhosis)
- Prognostic value: Identifies patients at risk for liver-related complications including hepatocellular carcinoma, decompensation, and death 1
Performance Characteristics:
FibroSure demonstrates good diagnostic accuracy for advanced fibrosis in NAFLD with an AUROC of approximately 0.84 2, 3. Using a cutoff of 0.48, it can effectively rule out advanced fibrosis 4. However, it does not outperform simpler calculations like FIB-4 in terms of diagnostic accuracy, though it remains a validated alternative 1.
NASH Assessment
Critical limitation: Neither standard liver profiles nor FibroSure can definitively diagnose NASH 1.
When combined with other biomarkers in the Fibromax panel, additional tests include:
- NashTest: Attempts to identify NASH but has suboptimal accuracy (sensitivity 83.3%, specificity 37.5%) 5
- SteatoTest: Assesses degree of hepatic steatosis 6
- ActiTest: Evaluates inflammatory activity 6
The evidence is clear that liver biopsy remains the reference standard for diagnosing NASH because available non-invasive tests lack acceptable accuracy for this specific diagnosis 4. FibroSure and related tests are better suited for fibrosis staging than NASH diagnosis.
Clinical Application Algorithm
For fibrosis risk stratification in NAFLD patients:
First-line screening: Calculate FIB-4 score using routine liver profile
- FIB-4 <1.3: Rules out advanced fibrosis (NPV >90%) 1
- FIB-4 >1.3: Proceed to secondary testing
Secondary assessment (when FIB-4 >1.3):
Indeterminate results: Consider liver biopsy for definitive staging
Key prognostic insight: Fibrosis stage, particularly advanced fibrosis (F3-F4), is the strongest predictor of liver-related mortality, hepatocellular carcinoma, and decompensation—making it more clinically relevant than NASH diagnosis alone 1.
Important Caveats
- Age affects accuracy: FIB-4 and similar scores may overestimate fibrosis in patients >65 years; higher cutoffs (FIB-4 >2.0) should be considered 4
- Obesity and diabetes: May reduce accuracy of some scores 4
- Cost consideration: FibroSure is proprietary and more expensive than FIB-4, which is free and equally validated 1
- Cannot replace biopsy for NASH diagnosis: If therapeutic decisions depend on confirming NASH histology, biopsy remains necessary 4
Bottom line: Use routine liver profile to calculate FIB-4 as your first step. Reserve FibroSure for secondary assessment when FIB-4 is elevated and elastography is unavailable. Neither test reliably diagnoses NASH—that requires biopsy 1, 4.