Liver blood tests are often done during health screening. A mildly abnormal result is common. It does not always mean serious disease, but it should not be ignored, because most liver conditions cause no symptoms until they are advanced.
What the tests measure
- ALT and AST: enzymes released when liver cells are irritated or injured
- ALP and GGT: raised when bile flow is affected, and GGT is often raised by alcohol
- Bilirubin: a yellow pigment; high levels cause jaundice
- Albumin and clotting tests: show how well the liver is working
Common causes
- Fatty liver, the most common cause
- Alcohol
- Hepatitis B, which is common in Singapore and often has no symptoms, and hepatitis C
- Medicines, traditional remedies and supplements, including some herbal and slimming products
- Gallstones blocking the bile duct
- Less common conditions, such as autoimmune hepatitis and primary biliary cholangitis
Hard exercise in the day or two before the test can raise AST and ALT from muscle. A slightly raised bilirubin on its own is often Gilbert’s syndrome, a common and harmless inherited condition.
Next steps
- A review of alcohol, medicines and supplements
- Repeat liver tests, and blood tests for hepatitis B and C and other causes
- An ultrasound scan of the liver
- A FibroScan to check for scarring
Bring your earlier results to your consultation, as the pattern over time is very helpful.
Seek urgent care at an emergency department for yellowing of the eyes with confusion or drowsiness, vomiting blood, or black stools.
General information only. Reviewed by Dr Chia Chung King, 2026-11-13. Book a consultation.