{"id":"fib-4","name":"FIB-4 Index","shortName":"FIB-4","aliases":["FIB-4","Fibrosis-4 Index","Fibrosis 4 Score","FIB4 Score","FIB4","Liver Fibrosis, FIB-4 Index","Índice FIB-4","FIB-4 Index Panel","Fibrosis-4 Score","Fibrosis 4 Index","FIB-4 Fibrosis Index","FIB-4 Score"],"abbreviations":["FIB-4","FIB4"],"loinc":[{"code":"98488-0","primary":true}],"specimen":"calculated","units":[{"ucum":"{index}","display":"index"}],"referenceRanges":[{"population":"18–64","low":null,"high":1.3,"unit":"{index}","unitDisplay":"index","note":"Below 1.3 is the usual low-risk cut-off for advanced fibrosis in adults with fatty liver disease. It is a risk cut-off, not a range taken from healthy people. Accuracy is lower under about 35, so results at those ages are read more cautiously. A score of exactly 1.3 sits on the edge: AASLD advises a second test at 1.3 or higher, while Shah 2009 reports the 90% negative predictive value at 1.30 or lower.","sources":[{"title":"AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC10735173/","publisher":"Hepatology (AASLD)","year":2023},{"title":"Comparison of noninvasive markers of fibrosis in patients with nonalcoholic fatty liver disease","url":"https://pubmed.ncbi.nlm.nih.gov/19523535/","publisher":"Clinical Gastroenterology and Hepatology","year":2009}]},{"population":"65+","low":null,"high":2,"unit":"{index}","unitDisplay":"index","note":"For adults aged 65 and older, a cut-off of 2.0 is used in place of 1.3, because the lower cut-off flags too many older people. AASLD 2023 says to use 2.0 above age 65.","sources":[{"title":"Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis","url":"https://pubmed.ncbi.nlm.nih.gov/27725647/","publisher":"American Journal of Gastroenterology","year":2017},{"title":"AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC10735173/","publisher":"Hepatology (AASLD)","year":2023}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"A score worked out from your age, AST, ALT and platelet count. It helps estimate the chance of advanced scarring (fibrosis) in the liver.","url":"https://bloodtesttracker.com/markers/fib-4","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}