VitalityCalculators
Last updated December 11, 2025

NAFLD Fibrosis Score Calculator

Also known as:NFS CalculatorNAFLD Fibrosis ScoreNon-Alcoholic Fatty Liver Disease Fibrosis ScoreLiver Fibrosis CalculatorAdvanced Fibrosis Score

Medically Reviewed

Dr. Masashi Yoneda, MD, PhD

Board-Certified Gastroenterologist & Hepatologist, NAFLD Researcher, Nihon University

·

Hepatology

Reviewed October 19, 2025

AASLD — NAFLD Practice Guidance

Disclaimer

The NAFLD Fibrosis Score is a validated clinical research tool intended to assist trained healthcare professionals in stratifying the risk of advanced hepatic fibrosis in patients with known or suspected non-alcoholic fatty liver disease. It is not a diagnostic test and should not be used as the sole basis for clinical decision-making. The score does not replace liver biopsy, imaging (FibroScan/VCTE), or clinical judgment. Results should always be interpreted in the context of the full clinical picture, patient history, and current evidence-based guidelines. Do not use this calculator for self-diagnosis. Always consult a qualified hepatologist or gastroenterologist.

Frequently Asked Questions

Everything you need to know about NAFLD and liver fibrosis scoring

The NAFLD Fibrosis Score Calculator is designed to estimate the likelihood of advanced liver fibrosis (F3–F4) in patients diagnosed with non-alcoholic fatty liver disease (NAFLD). It evaluates several clinical variables to provide a score that indicates the risk level of fibrosis, allowing for better management and treatment decisions.

To use the NAFLD Fibrosis Score Calculator, input the required six variables: age, body mass index (BMI), presence of type 2 diabetes or impaired fasting glucose, levels of AST (aspartate aminotransferase) and ALT (alanine aminotransferase), platelet count, and serum albumin levels. Once all data is entered, the calculator generates a score to indicate the risk of advanced fibrosis.

The NAFLD Fibrosis Score is calculated using a specific formula that incorporates the six variables mentioned. The formula is: NFS = -1.675 + (0.037 × Age) + (0.094 × BMI) + (1.13 × Diabetes) - (0.013 × Platelet Count) - (0.66 × Albumin) + (0.001 × AST) + (0.007 × ALT). Each variable plays a crucial role in determining the score, reflecting the multifactorial nature of liver health.

The results from the NAFLD Fibrosis Score categorize patients into three risk zones: scores below -1.455 suggest a low risk of advanced fibrosis, scores between -1.455 and 0.676 indicate an indeterminate risk that may require further evaluation, and scores above 0.676 suggest a high risk of advanced fibrosis. These classifications help guide clinicians in deciding on further diagnostic procedures or treatment plans.

In the context of the NAFLD Fibrosis Score, a score below -1.455 is considered to indicate a low risk of advanced fibrosis, while scores above 0.676 indicate a high risk. Scores within the indeterminate zone (-1.455 to 0.676) necessitate further clinical evaluation to determine the patient's liver health accurately.

One significant limitation of the NAFLD Fibrosis Score Calculator is that it is not a definitive diagnostic tool; it only provides an estimation of fibrosis risk based on the selected clinical parameters. Additionally, factors like liver histology, other liver diseases, and certain medications can influence the score. Therefore, it is essential to interpret the results in conjunction with clinical evaluations and potentially follow up with liver biopsy if needed.

The NAFLD Fibrosis Score Calculator is particularly useful for individuals diagnosed with non-alcoholic fatty liver disease (NAFLD) who are at risk for advanced liver fibrosis. It is typically used by healthcare providers to assess patients' risk profiles and determine the necessity for further testing or intervention. Patients with risk factors such as obesity, diabetes, or metabolic syndrome should also be considered for evaluation.

The frequency of using the NAFLD Fibrosis Score Calculator depends on individual patient circumstances, such as the progression of liver disease or changes in risk factors. Generally, it can be used annually or biennially in patients with stable conditions and no significant changes in their health status. However, if there are notable changes in symptoms or risk factors, more frequent assessments may be necessary.

Patients should consult a doctor if their NAFLD Fibrosis Score falls in the high-risk category (above 0.676) or if they receive an indeterminate score (between -1.455 and 0.676). Such scores indicate the need for further assessment and potential intervention. Additionally, any new symptoms or concerns regarding liver health should prompt a discussion with a healthcare provider.

When interpreting the NAFLD Fibrosis Score, it is essential to consider that the score may not account for all individual variations, such as ethnicity or other comorbidities that could affect liver health. Moreover, the score is based on non-invasive markers, which may not adequately reflect the full spectrum of liver pathology. Clinicians should combine the score with other assessments, including imaging studies and clinical evaluations.

The NAFLD Fibrosis Score Calculator is specifically validated for use in patients with non-alcoholic fatty liver disease (NAFLD) and may not be appropriate for those with other liver diseases, such as viral hepatitis or alcoholic liver disease. Using it in these populations may lead to misleading results, and alternative assessments tailored to those conditions should be considered.

The NAFLD Fibrosis Score provides a non-invasive alternative to liver biopsy, which is considered the gold standard for diagnosing liver fibrosis but carries risks like bleeding and infection. While the score can effectively stratify patients based on fibrosis risk, it may not capture all the nuances of liver pathology that a biopsy can. Therefore, while the calculator is useful for initial assessments, biopsy may still be warranted for definitive diagnosis in specific cases.

The NAFLD Fibrosis Score Calculator is primarily intended for adults, as the clinical parameters it uses may not be applicable to children or adolescents with NAFLD. Different scoring systems or evaluation methods may be necessary for younger populations. Therefore, healthcare providers should exercise caution when applying this tool to non-adult patients.

Patients with a high NAFLD Fibrosis Score may benefit from lifestyle modifications such as weight loss, dietary changes, and increased physical activity, which can help improve liver health and reduce the risk of advanced fibrosis. Consulting a healthcare provider or dietitian for personalized recommendations is advisable. These interventions should be part of a comprehensive approach to managing NAFLD and any associated metabolic conditions.

Certain medications can affect liver enzyme levels, which are included in the NAFLD Fibrosis Score calculation, potentially leading to inaccurate scores. Drugs that cause liver toxicity or alter metabolic processes may skew results, highlighting the importance of considering medication history during the evaluation. Patients should inform their healthcare provider of all medications, supplements, and over-the-counter drugs they are taking for accurate assessment.

NAFLD Fibrosis Score

Non-invasive assessment of liver fibrosis risk

years
kg/m²
U/L
U/L
×10⁹/L
g/dL

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