Understanding liver function tests

A liver function test panel measures substances linked with liver cells, bile flow and the liver's protein-making work. Results can help a clinician look for inflammation, blockage, injury or reduced function, but one result rarely explains the whole picture. Abnormal results can have several causes, including medicines, alcohol-related harm, viral hepatitis, fatty liver or problems outside the liver.

The panel may be requested because of symptoms, a physical finding, another blood result or medicine monitoring. The clinician compares results with earlier tests and considers your medical history, alcohol use, supplements and prescribed medicines.

Ask whether you need to avoid food or change medicines before the blood draw; do not stop a prescribed medicine unless the clinician tells you to. Tell the team about alcohol, over-the-counter products and herbal supplements. After testing, ask which markers were outside the expected range and whether repeat testing or imaging is needed.

A result is not a diagnosis by itself. Follow-up may involve reviewing medicines, checking for hepatitis, discussing alcohol use or investigating another cause. Keep the written result so it can be compared over time.

Seek urgent medical help for yellowing of the skin or eyes with confusion, severe drowsiness, vomiting blood, black stools, severe abdominal swelling or intense right-sided upper abdominal pain. Contact a clinician promptly for new jaundice, dark urine, pale stools or persistent vomiting, even if you feel otherwise well.

Why was this panel ordered? Which markers are abnormal, and what might explain them? Do I need repeat blood tests, imaging or hepatitis testing? Should any medicine, alcohol intake or supplement change while we investigate?