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AST-to-Platelet Ratio Index (APRI Score)Acute Liver Failure Study Group Index (ALFSG Index)Age, Bilirubin, INR and Creatinine Score (ABIC Score)Albumin-Bilirubin Grade (ALBI Score)BMI, AST/ALT Ratio, and Diabetes Score (BARD Score)CLIF-C ACLF Score for Acute-on-Chronic Liver Failure (CLIF-C ACLF)CLIF-C AD Score for Acute Decompensation of Cirrhosis (CLIF-C AD)CLIF-SOFA Score for Organ Failure Assessment (CLIF-SOFA)Cancer of the Liver Italian Program Score (CLIP Score)Child-Pugh Classification for Cirrhosis (Child-Pugh)Chinese University Prognostic Index (CUPI Score)Fibrosis-4 Index (FIB-4 Index)Lille Model for Alcoholic Hepatitis (Lille Model)Maddrey Discriminant Function (Maddrey DF)Model for End-Stage Liver Disease (MELD Score)NAFLD Fibrosis Score (NFS)Simplified Autoimmune Hepatitis Score (Simplified AIH)
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NAFLD Fibrosis Score (NFS)

NAFLD Fibrosis Score (NFS)

Fibrosis Prediction in Fatty Liver Disease

Cutoff > 0.676 = Advanced fibrosis (F3–F4)

NAFLD Engine

Enter clinical variables to predict advanced hepatic fibrosis in NAFLD patients.

Guidelines & Evidence

Verified

Last Review: 2026-07-17

Clinical Significance

The Global Burden of NAFLD

NAFLD is the most common cause of chronic liver disease globally. While most patients have simple steatosis, those with advanced fibrosis are at the highest risk for cirrhosis, liver failure, and hepatocellular carcinoma.

Avoiding Unnecessary Biopsies

Liver biopsy is invasive and costly. The NFS helps clinicians "rule out" advanced fibrosis with high accuracy, identifying low-risk patients who can be managed in primary care without specialist referral.

The Metabolic Syndrome Link

The NFS specifically incorporates obesity and hyperglycemia (Diabetes status), recognizing that metabolic syndrome is the primary driver of liver scarring in fatty liver disease.

How it Works

Variables Required

Age: Years.
BMI: kg/m².
Hyperglycemia/Diabetes: Yes/No.
AST/ALT Ratio: Reflects metabolic liver stress.
Platelet Count: Marker of portal hypertension.
Albumin: Marker of synthetic function.

The Scoring Formula

NFS = -1.675 + 0.037 × age (y) + 0.094 × BMI (kg/m²) + 1.13 × IFG/diabetes (yes=1, no=0) + 0.99 × AST/ALT ratio - 0.013 × platelet (×10⁹/L) - 0.66 × albumin (g/dL)

Interpretation Thresholds

Low Cutoff: < -1.455 (Rules out advanced fibrosis). High Cutoff: > 0.675 (Rules in advanced fibrosis).

Clinical Pearls

Negative Predictive Value (NPV)

The primary strength of the NFS is its NPV (~93%). If a patient scores < -1.455, you can be 93% confident they do not have advanced fibrosis.

The "Indeterminate" Zone

Scores between -1.455 and 0.675 are indeterminate. Roughly 25-30% of patients fall here and require a "tie-breaker" test like FibroScan (VCTE).

Age Sensitivity

In patients over age 65, the NFS (and FIB-4) can be falsely elevated. Use a higher low-cutoff (-0.12) to avoid over-diagnosing fibrosis in the elderly.

Platelet Trend

A falling platelet count in a patient with NAFLD is a late sign of portal hypertension and should prompt immediate evaluation for cirrhosis.

Next Steps

Low Risk (Score < -1.455)

Manage metabolic risk factors (Diabetes, HTN, Lipids).
Lifestyle modifications (Weight loss, Exercise).
Repeat NFS every 2-3 years.

Indeterminate/High Risk (Score > -1.455)

Order a secondary non-invasive test (FibroScan/VCTE).
If FibroScan stiffness > 8 kPa, refer to Hepatology.
Evaluate for HCC surveillance if cirrhosis is suspected.

The Evidence

Original Validation

The NAFLD fibrosis score: a noninvasive system that identifies liver fibrosis in patients with NAFLD.

Angulo P et al. • Hepatology. 2007;Study of 733 biopsy-proven patients. Proved high diagnostic accuracy across different ethnic groups and degrees of obesity.

Global Guideline Endorsement

The diagnosis and management of NAFLD: Practice guidance from the AASLD.

Chalasani N et al. • Hepatology. 2018;Recommended NFS as a standard tool for evaluating fibrosis risk in all patients with fatty liver.

Origins & History

Development at Mayo Clinic

The NFS was developed by Dr. Paul Angulo and colleagues at the Mayo Clinic. It was part of the first generation of purely biochemical and clinical scores designed to combat the rising "epidemic" of fatty liver disease.

Evolution of NITs

Along with FIB-4, the NFS changed the standard of care by shifting fibrosis assessment from the interventional radiology suite to the primary care physician's office.

Last Comprehensive Review: 2026-07-17

In Recent Clinical News

Scanning Medical Journals

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