Liver Function Tests

Liver function tests are blood tests used to help diagnose and monitor liver disease or damage. The tests measure the levels of certain enzymes and proteins in your blood. Some of these tests measure how well the liver is performing its normal functions of producing protein and clearing bilirubin, a blood waste product. Other liver function tests measure enzymes that liver cells release in response to damage or disease. Abnormal liver function test results don't always indicate liver disease. Your doctor will explain your results and what they mean.

Why Are Liver Function Tests Done?

  • Lack of appetite
  • Nausea or vomiting
  • Weakness or feeling very tired
  • Yellowish eyes or skin (jaundice)
  • Dark urine or light-colored poop (less common)
  • Swelling in your belly (less common)

Your doctor may order a liver test if you’re more likely to have liver damage or disease, like if you:

  • Drink heavily or have an alcohol use disorder
  • Have a family member with liver disease
  • Are very overweight, especially if you also have diabetes or high blood pressure
  • Take medicine that can harm your liver
  • Have gallbladder disease or anemia

The liver test can also help your doctor learn whether an illness is getting worse or how well treatment is working.

How to Prepare for a Liver Function Test ?

Make sure to tell your doctor about any medicines you’re taking, including over-the-counter medications and herbal supplements. They may tell you to stop eating the night before the test.

What you can expect

During the test:The blood sample for liver function tests is usually drawn through a small needle inserted into a vein in the bend of your arm. The needle is attached to a small tube, to collect your blood. You may feel a quick pain as the needle is inserted into your arm and experience some short-term discomfort at the site after the needle is removed.

After the test: Your blood will be sent to a laboratory for analysis. If the lab analysis is done on-site, you could have your test results within hours. If your doctor sends your blood to an off-site laboratory, you may receive the results within several days.