NAFLD Fibrosis Score Calculator

Your details

Patient age in years. The score was validated in adults aged 18 and older.
years
Choose whether to enter your BMI directly or calculate it from height and weight.
Body Mass Index in kg/m². Normal range is 18.5-24.9.
kg/m²
Set to Yes if the patient has type 2 diabetes mellitus or impaired fasting glucose (fasting glucose 100-125 mg/dL). This variable is coded as 1 in the formula.
Serum AST level. Normal adult upper limit is approximately 40 IU/L.
IU/L
Serum ALT level. Normal adult upper limit is approximately 40 IU/L.
IU/L
Platelet count in 10⁹/L (or 10³/μL). A falling platelet count can indicate portal hypertension from advancing fibrosis.
×10⁹/L
Serum albumin in g/dL. Normal range is 3.5-5.0 g/dL. Low albumin may indicate impaired hepatic synthetic function.
g/dL
NAFLD Fibrosis ScoreLow fibrosis probability
-1.623

Numerical score on the NFS scale

AST/ALT ratio0.82
BMI used28kg/m²
Fibrosis probabilityLow probability (F0-F2, no advanced fibrosis)
-1.623
Low (F0-F2)<-1.455Indeterminate-1.455-0.676High (F3-F4)0.676+

NFS -1.623: low probability of advanced fibrosis.

  • Your NFS of -1.623 is below -1.455, which corresponds to a low probability of advanced fibrosis (stages F0-F2). The original study reported a negative predictive value of 93% at this cutoff.
  • This result suggests that advanced fibrosis can be excluded with reasonable confidence, potentially avoiding the need for liver biopsy.
  • The AST/ALT ratio used in the formula is 0.82. A ratio above 1.0 can indicate more advanced liver disease, as AST rises relative to ALT as fibrosis progresses.

Next stepContinue monitoring with periodic liver function tests. Lifestyle changes including weight loss and exercise remain important for managing NAFLD even at low fibrosis stages.

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