How this calculator works
Angulo and colleagues developed this index in adults with NAFLD. Its historical name is retained because the model predates MASLD terminology. It combines age, BMI, impaired fasting glucose or diabetes, AST/ALT, platelets and albumin. Original cut-offs were -1.455 and 0.676. The score performs differently across ages and populations and is not a diagnosis; current pathways may prefer FIB-4 followed by additional assessment. Inverse modes are algebraic consistency checks, not replacements for laboratory or anthropometric measurements. The result is an estimate for information only and is not medical advice.
Formula
NFS = -1.675 + 0.037 x age(years) + 0.094 x BMI + 1.13 x diabetes/IFG indicator + 0.99 x AST/ALT - 0.013 x platelets(10^9/L) - 0.66 x albumin(g/dL). BMI = weight kg / height m squared.
Worked example
Age 50, BMI 25, no diabetes/IFG, AST/ALT 1, platelets 200 and albumin 4 give NFS -1.725. Changing only the indicator to yes adds 1.13, giving -0.595.
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Frequently asked questions
Does a low result exclude all liver disease?
No. It is a fibrosis risk estimate in a defined population, not a general liver health test.
How do I enter diabetes or IFG?
Use a clinically established finding, not an isolated symptom or a guessed glucose status.
What units does the solved input use?
Age uses years, height metres, weight kilograms, AST/ALT U/L, platelets 10^9/L and albumin g/dL, as labelled in the input fields.