FIB-4 Index (Fibrosis-4)
Here’s what it reflects — and what to do about it.
Longetic pulls together every lab and record you’ve had, follows how FIB-4 Index (Fibrosis-4) changes over time, and explains what’s shifting — so you walk into your next appointment prepared, with reminders for retests along the way.
What is FIB-4 Index (Fibrosis-4)?
A calculated score using age and routine blood tests to estimate the likelihood of significant liver scarring (fibrosis).
FIB-4 is a calculated value: it combines your age, two liver enzymes (AST and ALT), and your platelet count using (Age times AST) divided by (Platelets times the square root of ALT). It was developed as a simple, non-invasive way to gauge liver scarring without a biopsy. A higher FIB-4 can be associated with a greater likelihood of advanced fibrosis, a low value makes advanced scarring less likely. It is a risk estimate that guides further evaluation, not a diagnosis.
What to know about FIB-4 Index (Fibrosis-4)
Understanding FIB-4 Index (Fibrosis-4) means knowing what it reflects, what tends to move it, and the signs that suggest it’s worth a closer look — so you can bring the right questions to your next appointment.
This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Medical Disclaimer.
References
About our sources
Official sources
Government health agencies, national institutes, and intergovernmental bodies whose guidelines carry regulatory or policy weight.
Clinical / professional
Medical societies, specialty colleges, and professional associations whose consensus statements reflect clinical practice standards.
Peer-reviewed research
Original research articles and systematic reviews published in indexed journals and verified through PubMed or DOI.