NAFLD Fibrosis Score Calculator
This NAFLD fibrosis score calculator identifies liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). It estimates the progression of scarring in the liver based on a few laboratory tests, can be used to predict the risk of end-stage liver disease and can evaluate the progression or stabilization of said liver disease. Read the article below to find out more about NAFLD, the NAFLD score formula and the NAFLD score interpretation.
If you are interested in other calculators related to the liver disease, check the MELD calculator (Model for End-Stage Liver Disease), FIB-4 calculator, and APRI calculator (AST to Platelet Ratio Index).
We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment.
Non-alcoholic fatty liver disease (NAFLD)
Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease worldwide. It is assumed that this disorder is present in approximately 25% of the world's population. NAFLD is associated with an excessive fat build-up in the liver without another clear cause, e.g. alcohol use. Usually it does not give noticeable signs and is often diagnosed during routine health checks. In some cases, NAFLD can cause symptoms related to liver dysfunction, which include fatigue, malaise, or mild yellow discoloration of the skin. NAFLD may eventually lead to complications such as cirrhosis, liver cancer, liver failure, or cardiovascular disease.
The risk factors of NAFLD include:
- Being overweight or obese;
- Metabolic syndrome;
- Diet rich in fructose; and
- Older age.
NAFLD fibrosis score
Liver biopsy is considered to be the gold standard for the diagnosis and assessment of liver fibrosis, however this method has several limitations, which include high cost and invasiveness. Therefore, a noninvasive indicator of liver fibrosis in patients with NAFLD has been developed - the NAFLD fibrosis score.
It consists of six following components:
- Presence of hyperglycemia;
- BMI (body mass index);
- Platelet count;
- Albumin level; and
- Aspartate aminotransferase and alanine aminotransferase ratio - find out more in a dedicated (AST/ALT) ratio calculator.
The NAFLD fibrosis score was found to independently identify NAFLD patients with and without advanced fibrosis at the initial NAFLD diagnosis. Moreover, several studies validated it and confirmed that it has acceptable sensitivity, specificity, and positive and negative predictive values for advanced liver fibrosis.
NAFLD score formula
NAFLD fibrosis score calculator uses the following formula to compute the NAFLD fibrosis score:
NFS = -1.675 + (0.037 × age) + (0.094 × BMI) + (1.13 × hyperglycemia) + (0.99 × AST/ALT ratio) - (0.013 × platelet count) - (0.66 × albumin)
NFS - NAFLD fibrosis score;
age - age expressed in years;
BMI - Body Mass Index expressed in kg/m² (the NAFLD fibrosis score calculator calculates it for you);
hyperglycemia - presence of impaired fasting glucose or diabetes (yes = 1, no = 0);
AST/ALT ratio - AST and ALT levels expressed in IU/L (the NAFLD fibrosis score calculator calculates AST/ALT ratio for you);
platelet count - platelet count expressed in 10⁹/L; and
albumin - albumin level expressed in g/dL (the NAFLD fibrosis score calculator can also convert it from g/L).
NAFLD fibrosis score range
The following NAFLD fibrosis score range is used to identify liver fibrosis:
NAFLD fibrosis score
Less than -1.455
Low probability of fibrosis
From -1.455 to 0.676
More than 0.676
High probability of fibrosis at baseline
A score lower than -1.455 can exclude advanced fibrosis with a high accuracy, whereas score higher than 0.676 is highly indicative of advanced fibrosis. Applying this model may help avoid unnecessary liver biopsy.