NAFLD Fibrosis Score (NFS) Calculator
Use this tool to estimate the NAFLD Fibrosis Score (NFS), a non-invasive score used to help assess the likelihood of advanced liver fibrosis in adults with fatty liver disease.
What is the NFS score?
The NAFLD Fibrosis Score (NFS) is a clinical risk score that combines routine patient and laboratory data to estimate the probability of advanced fibrosis in people with non-alcoholic fatty liver disease (NAFLD). It is widely used because it is simple, inexpensive, and does not require specialized imaging.
This nfs score calculator is designed for educational and screening support. It helps identify who may be at lower risk, who may need further evaluation, and who may benefit from specialist referral.
Inputs used in this calculator
- Age: Older age increases score and fibrosis risk.
- BMI: Higher BMI is associated with metabolic liver risk.
- Impaired fasting glucose or diabetes: Metabolic disease strongly influences fibrosis progression.
- AST/ALT ratio: Derived from liver enzyme levels.
- Platelet count: Lower platelets may reflect portal hypertension or advanced liver disease.
- Albumin: Lower albumin can indicate reduced liver synthetic function.
NFS formula
The score is calculated as:
NFS = -1.675 + (0.037 × age) + (0.094 × BMI) + (1.13 × diabetes/IFG) + (0.99 × AST/ALT ratio) - (0.013 × platelets) - (0.66 × albumin)
In the formula, diabetes/IFG is coded as 1 for yes and 0 for no.
How to interpret your result
- NFS < -1.455: Lower likelihood of advanced fibrosis.
- NFS between -1.455 and 0.676: Indeterminate range (more testing is often needed).
- NFS > 0.676: Higher likelihood of advanced fibrosis.
When this nfs score calculator is most useful
Primary care triage
If a patient has fatty liver on imaging or persistent liver enzyme elevation, NFS can be a practical first-pass tool to stratify risk before more advanced tests.
Metabolic clinic follow-up
In patients with obesity, type 2 diabetes, dyslipidemia, or metabolic syndrome, NFS can support longitudinal risk discussions and care planning.
Shared decision-making
A structured score helps clinicians explain why additional tests (e.g., elastography) may or may not be necessary.
Limitations you should know
- NFS is a screening and risk-stratification tool, not a stand-alone diagnosis.
- Values in the indeterminate zone are common and require further evaluation.
- Lab variability, acute illness, or medication effects can influence the result.
- Older age can raise score independently and may reduce specificity in elderly populations.
What to do after calculating NFS
- Review score category (low, indeterminate, high).
- Compare with clinical context: symptoms, comorbidities, alcohol history, medication profile.
- Consider additional non-invasive testing (e.g., transient elastography, ELF, or FIB-4 pathway depending on local protocol).
- If high risk, discuss hepatology referral.