Liver function tests (ALT, AST, bilirubin)
liver function test · LFT · liver panel · ALT and AST · bilirubin test
This is a blood test from a vein. It shows how well your liver works and whether it is inflamed.
For weakness, yellowish skin, pain under the right ribs, while taking certain medicines, or at a checkup.
⏱ Duration: the blood draw takes a few minutes; results usually come the next day
Be sure to tell your doctor
How to prepare
- Food. Usually fasting: no food for 8 to 12 hours. Plain water is fine. Check with the lab.
- The day before. For 1 to 2 days, no alcohol and no fatty or fried food. No hard workouts.
- Medicines. Do not stop them on your own. Tell your doctor what you take. They will decide if anything should change.
What to bring
- Your test request form
- Your ID
- Past test results, if you have them
How it goes
- You sit down and rest your arm on the armrest
- A band is tightened above your elbow
- The skin is wiped with antiseptic
- A quick prick, and blood fills a tube
- The needle comes out, and a cotton pad is pressed on the spot
What you'll feel
- A quick prick, like a pinch
- Sometimes slight dizziness. Tell the nurse
Afterwards
- Press the cotton pad for 3 to 5 minutes and keep your arm straight
- You can eat right away and go back to your usual day
- Results usually come in 1 day. The lab will tell you when
- Your doctor will explain what the numbers mean
Common questions
Why can ALT be high?
There are many reasons: fatty food, alcohol, medicines, exercise, or liver disease. Your doctor will sort it out. Often the test is simply repeated.
Can I drink coffee before the test?
No, if the test is fasting. Plain water only.