NAFLD (Non-Alcoholic Fatty Liver Disease) Fibrosis Score
Estimates amount of scarring in the liver based on several laboratory tests.
Creator
Dr. Paul Angulo (d. 2015), MDInstructions
The NAFLD Fibrosis Score estimates the probability of advanced liver fibrosis (stage F3-F4) in patients with non-alcoholic fatty liver disease(NAFLD).
Min 0 – Max 120
The NAFLD Fibrosis Score (NFS) estimates whether a patient with nonalcoholic fatty liver disease (NAFLD) has advanced liver scarring (fibrosis) using routine clinical information and blood tests. Paul Angulo, MD, and an international team of colleagues developed it in 2007. They built it from 733 patients with biopsy-confirmed NAFLD, split into groups to construct (480) and validate (253) the score. Patients with NAFLD and advanced fibrosis are at the highest risk of progressing to end-stage liver disease, so the score helps clinicians decide who needs further testing or specialist referral. It’s sorted into either advanced fibrosis (stages F3–F4) or no advanced fibrosis (stages F0–F2).
Fatty liver disease has been renamed. In 2023, international liver societies replaced “NAFLD” with MASLD (metabolic dysfunction-associated steatotic liver disease).
What it needs: Six variables: age (years), BMI (kg/m²), impaired fasting glucose or diabetes, AST/ALT ratio, platelet count, and albumin (g/dL). Diabetes or impaired fasting glucose is entered as yes (1) or no (0).
How it’s calculated:
NAFLD Score = -1.675 + (0.037*age [years]) + (0.094*BMI [kg/m²]) + (1.13*IFG/diabetes [yes = 1, no = 0]) + (0.99*AST/ALT ratio) – (0.013*platelet count [×10⁹/L]) – (0.66*albumin [g/dl])
Results
NAFLD Score (<-1.455) - Correlated Fibrosis Severity: F0-F2
Advanced fibrosis (F3-F4) is unlikely; this cut-off is applied to rule out advanced fibrosis.
The score can be used to reliably predict (with high 80-low 90% accuracy) which patients are unlikely to have cellular evidence of fibrosis on biopsy.
NAFLD Score (-1.455 to 0.675) - Correlated Fibrosis Severity: Indeterminant score
Advanced fibrosis can be neither ruled in nor ruled out; further assessment or specialist referral may be considered.
NAFLD Score (>0.675) - Correlated Fibrosis Severity: F3-F4
Advanced fibrosis is likely; this cut-off is applied to rule in advanced fibrosis.
Management Considerations:
The accuracy of results can be impacted by extremely elevated BMI. If your patient is morbidly obese, consider using a fibrosis score that does not incorporate BMI, such as FIB-4.
Fibrosis Severity Scale
F0 = no fibrosis
F1 = mild fibrosis
F2 = moderate fibrosis
F3 = severe fibrosis
F4 = cirrhosis
All questions & possible results
Clinical and laboratory valuesTitle not visible
Age
A number between 0 and 120 (whole numbers), in years.
Body mass index
Impaired fasting glucose or diabetes
Select one option:
- No
- Yes
AST
Normal Range: 15-41 U/L
A number between 1 and 200 (whole numbers), in U/L.
ALT
Normal Range: 1-35 U/L
A number between 1 and 200 (whole numbers), in U/L.
Platelet count
Normal Range: 150-350
A number between 1 and 1000 (whole numbers), in x10⁹/L or x10³/μL.
Albumin
Normal Range:
3.5-5.5 g/dL
35-55 g/L
A number between 1 and 7, in g/dL or g/L.
Possible results
NAFLD Score (<-1.455) - Correlated Fibrosis Severity: F0-F2
Advanced fibrosis (F3-F4) is unlikely; this cut-off is applied to rule out advanced fibrosis.
The score can be used to reliably predict (with high 80-low 90% accuracy) which patients are unlikely to have cellular evidence of fibrosis on biopsy.
The accuracy of results can be impacted by extremely elevated BMI. If your patient is morbidly obese, consider using a fibrosis score that does not incorporate BMI, such as FIB-4.
Fibrosis Severity Scale
F0 = no fibrosis
F1 = mild fibrosis
F2 = moderate fibrosis
F3 = severe fibrosis
F4 = cirrhosis
NAFLD Score (>0.675) - Correlated Fibrosis Severity: F3-F4
Advanced fibrosis is likely; this cut-off is applied to rule in advanced fibrosis.
The accuracy of results can be impacted by extremely elevated BMI. If your patient is morbidly obese, consider using a fibrosis score that does not incorporate BMI, such as FIB-4.
Fibrosis Severity Scale
F0 = no fibrosis
F1 = mild fibrosis
F2 = moderate fibrosis
F3 = severe fibrosis
F4 = cirrhosis
NAFLD Score (-1.455 to 0.675) - Correlated Fibrosis Severity: Indeterminant score
Citation
Literature
Angulo P, Hui JM, Marchesini G, Bugianesi E, George J, Farrell GC, Enders F, Saksena S, Burt AD, Bida JP, Lindor K, Sanderson SO, Lenzi M, Adams LA, Kench J, Therneau TM, Day CP. The NAFLD fibrosis score: a noninvasive system that identifies liver fibrosis in patients with NAFLD. Hepatology. 2007 Apr;45(4):846-54.
https://pubmed.ncbi.nlm.nih.gov/17393509/Treeprasertsuk S, Björnsson E, Enders F, Suwanwalaikorn S, Lindor KD. NAFLD fibrosis score: a prognostic predictor for mortality and liver complications among NAFLD patients. World J Gastroenterol. 2013 Feb 28;19(8):1219-29.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3587478/Drolz A, Wolter S, Wehmeyer MH, Piecha F, Horvatits T, Schulze Zur Wiesch J, Lohse AW, Mann O, Kluwe J. Performance of non-invasive fibrosis scores in non-alcoholic fatty liver disease with and without morbid obesity. Int J Obes (Lond). 2021 Oct;45(10):2197-2204.
https://pubmed.ncbi.nlm.nih.gov/34168277/Arnouk J, Rachakonda VP, Jaiyeola D, Behari J. Differential Outcomes and Clinical Challenges of NAFLD With Extreme Obesity. Hepatol Commun. 2020 Jul 21;4(10):1419-1429.
https://pubmed.ncbi.nlm.nih.gov/33024913/Qadri S, Ahlholm N, Lønsmann I, Pellegrini P, Poikola A, Luukkonen PK, Porthan K, Juuti A, Sammalkorpi H, Penttilä AK, D'Ambrosio R, Soardo G, Leeming DJ, Karsdal M, Arola J, Kechagias S, Pelusi S, Ekstedt M, Valenti L, Hagström H, Yki-Järvinen H. Obesity Modifies the Performance of Fibrosis Biomarkers in Nonalcoholic Fatty Liver Disease. J Clin Endocrinol Metab. 2022 Apr 19;107(5):e2008-e2020.
https://pubmed.ncbi.nlm.nih.gov/34971370/
- Creator
- Provided by
EVAL Foundation
- Contributor · Reviewer
Jennifer Glen, DNP, FNP-BCEVAL Health, Chief Medical Officer EVAL Foundation
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