What happens during the test?
A technician or nurse wraps a wide elastic band around your upper arm to help locate the vein.
Once the vein is located, usually on the inside of your elbow, the area is disinfected using alcohol swabs. The technician inserts a needle into a vein and pushes a vial (labelled with your name and other information) onto the needle to collect the blood. The elastic band is removed and after the blood is collected, the needle removed and discarded. You will have to hold a small piece of cotton over the area until bleeding stops. A small bandage will be applied to hold the cotton in place.
The technician wears fresh latex gloves and uses a new, single-use needle for each procedure.
The test is almost painless for most people, although feeling a slight pinch when the needle is inserted is normal. The vials of blood are then sent to a laboratory to be tested.
How should I prepare for this test?
In most cases you do not need to do anything to prepare for this test.
Clothing with no sleeves or loose sleeves is recommended so your upper arm can be exposed.
Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any medication allergies and medical conditions that you may have.
If your doctor asks you to fast (starting at midnight on the night before your test), do not eat or drink anything until the test has been done. You may also be advised not to consume any alcohol for 24 hours prior to the test.
Ask your doctor or pharmacist whether you need to stop taking any of your medications before the test.
What can I expect after the test?
Slight tenderness may occur where the needle was inserted. Keep pressure on the area after the needle is removed to prevent bruising.
Results
Your doctor reviews the results from the laboratory. Ask your doctor when your test results should be available.
Results return in the form of a number.
Higher-than-average numbers are a possible sign of liver damage. If the results are high for a long period of time, this could mean you have a chronic liver infection (e.g., hepatitis C virus) or chronic liver disease. High liver enzymes may occur for many other reasons, including:
- viral or bacterial infections
- certain medications (e.g., some cholesterol-lowering medications)
- excessive use of alcohol
- joint- and bone-related problems
- certain types of cancer
- diabetes that has been poorly controlled
- gall bladder diseases
To diagnose a specific condition, your doctor may need you to do further tests.