NAFLD Fibrosis Score
Calculate NAFLD fibrosis score using age, BMI, AST/ALT ratio, platelet count, and albumin. Free non-invasive liver fibrosis risk assessment tool with interpretation and charts.
About This Calculator
The NAFLD Fibrosis Score (NFS) is a validated non-invasive scoring system that estimates the likelihood of advanced liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). Developed by Angulo et al. in 2007 and published in Hepatology, the NFS combines six readily available clinical and laboratory variables — age, BMI, hyperglycemia status, AST/ALT ratio, platelet count, and albumin — to stratify patients into low, intermediate, or high probability of advanced fibrosis.
The score is calculated using the formula: NFS = -1.675 + (0.037 × age) + (0.094 × BMI) + (1.13 × IFG/diabetes) + (0.99 × AST/ALT) − (0.013 × platelet count) − (0.66 × albumin). A score below −1.455 suggests F0-F2 fibrosis (low risk), while a score above 0.676 suggests F3-F4 advanced fibrosis (high risk). Scores in the middle range are indeterminate and may require additional testing such as liver elastography or biopsy.
The NAFLD fibrosis score has been validated in diverse populations worldwide and is recommended by major hepatology guidelines including AASLD (American Association for the Study of Liver Diseases), EASL (European Association for the Study of the Liver), and INASL (Indian National Association for Study of the Liver). It remains one of the most widely used non-invasive tools for fibrosis assessment in NAFLD patients, helping to reduce unnecessary liver biopsies.
Regional Notes
US: AASLD guidelines recommend NFS as a first-line non-invasive test for fibrosis risk stratification in NAFLD. The score is used alongside FIB-4 and elastography in clinical practice.
UK: NICE guidelines recommend NFS for primary care assessment of NAFLD patients. The score is commonly used in NHS hepatology and gastroenterology departments for triaging patients who need specialist referral.
India: INASL guidelines endorse NFS for fibrosis assessment given the high prevalence of NAFLD and metabolic syndrome. The score is widely used in Indian hepatology practice and research studies.
Frequently Asked Questions
What is the NAFLD fibrosis score?
The NAFLD fibrosis score (NFS) is a non-invasive scoring system that uses six clinical and laboratory variables to estimate the likelihood of advanced liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). It was developed by Angulo et al. in 2007 and validated in multiple studies worldwide.
How is the NAFLD fibrosis score calculated?
The NAFLD fibrosis score is calculated using the formula: NFS = -1.675 + (0.037 × age in years) + (0.094 × BMI) + (1.13 × IFG/diabetes) + (0.99 × AST/ALT ratio) - (0.013 × platelet count in 10⁹/L) - (0.66 × albumin in g/dL). The calculator computes BMI and AST/ALT ratio automatically from your inputs.
What do the NAFLD fibrosis score results mean?
A score below -1.455 indicates low probability of advanced fibrosis (F0-F2), a score between -1.455 and 0.676 is intermediate or indeterminate, and a score above 0.676 indicates high probability of advanced fibrosis (F3-F4). Scores in the indeterminate range may require further evaluation such as liver biopsy or elastography.
Can the NAFLD fibrosis score replace a liver biopsy?
The NAFLD fibrosis score can help identify patients who are likely or unlikely to have advanced fibrosis, potentially reducing the need for liver biopsy. However, it is not a replacement for clinical evaluation. Scores in the indeterminate range still require further assessment, and all results should be discussed with a healthcare provider.
How accurate is the NAFLD fibrosis score?
Studies show that the NAFLD fibrosis score has good diagnostic accuracy. A score below -1.455 can exclude advanced fibrosis with a negative predictive value of about 88-93%, while a score above 0.676 can confirm advanced fibrosis with a positive predictive value of about 82-90%. About 25-30% of patients fall into the indeterminate zone.
Is the NAFLD fibrosis score used in the US, UK, and India?
Yes, the NAFLD fibrosis score is used globally including in the US, UK, and India. It was validated in multi-center international studies and is recommended by major hepatology guidelines including AASLD (US), EASL (Europe), and INASL (India). The formula uses standard lab values that are measured uniformly worldwide.
What tests do I need for the NAFLD fibrosis score?
The NAFLD fibrosis score requires routine blood tests that are part of standard liver function panels: AST (aspartate aminotransferase), ALT (alanine aminotransferase), platelet count, and albumin. You also need your age, height, weight, and knowledge of whether you have impaired fasting glucose or diabetes.
Can I rely on this calculator for diagnosis?
No. This calculator is for educational and reference purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional for proper evaluation of liver disease and fibrosis risk.