Fibrosis-4(FIB-4)
= age [years] x AST [U/L]/(platelet [10⁹/L] x (ALT [U/L])^1/2

*not accurate in age <35 y and lower rule-out threshold among high-risk individuals who have high pretest probability

參考文獻 References: 

• European Association for the Study of the Liver. (2015). EASL-ALEH Clinical Practice Guidelines: Non-invasive tests for evaluation of liver disease severity and prognosis. Journal of hepatology, 63(1), 237-264.
• McPherson, Stuart, et al. "Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis." The American journal of gastroenterology 112.5 (2017): 740.
• Barb, Diana, et al. "Type 2 diabetes mellitus increases the risk of hepatic fibrosis in individuals with obesity and nonalcoholic fatty liver disease." Obesity 29.11 (2021): 1950-1960.
• Graupera, Isabel, et al. "Low accuracy of FIB-4 and NAFLD fibrosis scores for screening for liver fibrosis in the population." Clinical Gastroenterology and Hepatology 20.11 (2022): 2567-2576.

AST to Platelet Ratio Index (APRI) 
= AST [U/L] /ULN/Platelet [10⁹/L] x 100

References: 

• European Association for the Study of the Liver. (2015). EASL-ALEH Clinical Practice Guidelines: Non-invasive tests for evaluation of liver disease severity and prognosis. Journal of hepatology, 63(1), 237-264.
• Sripongpun, Pimsiri, et al. "Evaluation of aspartate aminotransferase to platelet ratio index and fibrosis 4 scores for hepatic fibrosis assessment compared with transient elastography in chronic hepatitis C patients." JGH Open 4.1 (2020): 69-74.

NAFLD fibrosis score (NFS) 
= -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 [X10⁹/L]) – (0.66*Albumin [g/dl])

*not accurate in age <35 y, people with obesity and/or type 2 diabetes

References: 

• Mellitus, D. The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 1997, 20, 1183–1197. 
• McPherson, Stuart, et al. "Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis." The American journal of gastroenterology 112.5 (2017): 740.
• Barb, Diana, et al. "Type 2 diabetes mellitus increases the risk of hepatic fibrosis in individuals with obesity and nonalcoholic fatty liver disease." Obesity 29.11 (2021): 1950-1960.
• Graupera, Isabel, et al. "Low accuracy of FIB-4 and NAFLD fibrosis scores for screening for liver fibrosis in the population." Clinical Gastroenterology and Hepatology 20.11 (2022): 2567-2576.

Fatty liver index (FLI) 
= (e 0.953*loge (triglycerides) + 0.139*BMI + 0.718*loge (ggt) +
    0.053*waist circumference - 15.745) / (1 + e 0.953*loge (triglycerides) +
    0.139*BMI + 0.718*loge (ggt) + 0.053*waist circumference - 15.745) * 100

References: 

• Rinella, Mary E., et al. "AASLD practice guidance on the clinical assessment and management of nonalcoholic fatty liver disease." Hepatology (2023): 10-1097.
• Bedogni, Giorgio, et al. "The Fatty Liver Index: a simple and accurate predictor of hepatic steatosis in the general population." BMC gastroenterology 6.1 (2006): 1-7.

Hepatic steatosis index (HSI) 
= 8 × (ALT / AST) + BMI + 2 (if diabetes) + 2 (if female)

References: 

• Lee, Jeong-Hoon, et al. "Hepatic steatosis index: a simple screening tool reflecting nonalcoholic fatty liver disease." Digestive and liver disease 42.7 (2010): 503-508.
• Sviklāne, Laura, et al. "Fatty liver index and hepatic steatosis index for prediction of non‐alcoholic fatty liver disease in type 1 diabetes." Journal of gastroenterology and hepatology 33.1 (2018): 270-276.