A blood test panel that measures liver enzymes and bilirubin levels to screen for hepatocellular injury, hepatic steatosis, hepatitis, and biliary tract problems.
Indication
- Evaluation of fatigue, loss of appetite, and jaundice (yellowing of the skin and sclera)
- Hepatocyte injury monitoring in addition to suspected viral hepatitis (B, C) screening
- Assessment of hepatic steatosis (fatty liver) and metabolic syndrome
- Monitoring of medications metabolized by the liver such as statins, antiepileptics, and paracetamol
- Evaluation of patients with suspected excessive alcohol use
- Periodic follow-up of known liver disease (hepatitis, cirrhosis)
- Routine pre-operative assessment
Preparation
- Fasting for 8-12 hours before the test is recommended; especially ideal for GGT
- No alcohol intake for 24 hours before the test is recommended
- Intense exercise can transiently elevate AST; vigorous exercise should be avoided before the test
- All medications and herbal supplements used should be reported to the physician
How it's performed
- Approximately 4-5 mL of blood is drawn from a vein in the arm
- Blood is collected in a red-top or yellow-top (gel) biochemistry tube
- Serum is separated by centrifugation and analyzed on an automated biochemistry analyzer
- ALT, AST, ALP, GGT, total bilirubin, and direct bilirubin levels are measured
- Results are typically reported within the same day
Post-procedure
- Results are interpreted by the physician together with the clinical picture
- For mild elevations, follow-up testing in 1-3 months may be requested
- For significant elevations, hepatitis serology, ultrasound, or gastroenterology consultation may be added
- For patients with steatosis, weight, nutrition, and exercise recommendations are provided
- If drug-induced elevation is suspected, the responsible medication is reviewed together with the physician
Risks
- Temporary bruising and tenderness at the blood draw site
- Rare hematoma
- Dizziness in people with needle phobia
- Very rarely, local infection
FAQ
What are the normal values for ALT and AST?
In adults, ALT and AST are generally accepted as below 40 IU/L. Small differences may exist by sex and laboratory; results slightly above the cutoff are not by themselves an indicator of disease.
Why might my liver enzymes be elevated?
The most common causes include hepatic steatosis, alcohol, certain medications (statins, paracetamol, antiepileptics), viral hepatitis, and intense exercise. A diagnosis cannot be made from a single test; your physician will evaluate the results together with the clinical picture.
Is fasting required?
Fasting for 8-12 hours is generally requested. Fasting is particularly important if GGT and triglycerides are being run together.
When should follow-up testing be done?
For mild elevations or medication monitoring, follow-up at 4-12 weeks is typically recommended based on the physician's advice.
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