Liver Function Test

What’s covered?

If your doctor has ordered a liver function test, there are a few things you should know about these tests. First of all, there are several different types of liver function tests that may be used on an individual patient, so it’s important to keep in mind that the results you may receive will vary depending on which tests were run.

Some of the most common types include:

● Alanine aminotransferase (ALT) – This test measures levels of enzymes associated with inflammation or damage to cells in the liver. High levels of ALT can indicate problems with any part of the liver cell cycle, from production to elimination. However, high levels are not always indicative of disease; high levels occur after strenuous exercise, for example.

● Aspartate transaminase (AST) – This test measures levels of enzymes present in liver cells, and is often used to help diagnose problems with the bile ducts or gallbladder. High levels of AST can indicate serious disease that requires treatment.

● Alkaline phosphatase (ALP) – ALP is typically produced by bone cells and liver cells (and other types, like intestine and placenta). The amount produced may decrease as a direct result of liver disease, but also due to medications like aspirin or birth control pills. If you are seeing your doctor because you believe there may be an issue with your liver function, it’s important to tell him or her if you are taking any medications, so they can take them into account when interpreting the results of your test.

● Bilirubin – This test measures the amount of bile that is present in a person’s blood, and is a measure of how well their liver cells are working. Elevated bilirubin levels may indicate diseases like hepatitis or cirrhosis, but also jaundice (as a result of an obstruction to the flow of bile from the liver) or Gilbert’s syndrome (which occurs when there is an underlying genetic problem). Low bilirubin levels generally do not indicate disease; however, it should be noted that people with darker skin have lower bilirubin levels than those with lighter skin.

● Albumin – This test may be done to determine how well the liver protein is producing albumin; it can indicate whether there are any problems with this protein’s production. If your doctor suspects that you have a problem with your albumin, he or she will more than likely order more specific tests of each component of the albumin molecule (for example, one antibody associated with hepatitis would help diagnose hepatitis).

● Prothrombin time – This test measures blood clotting ability and serves as an indicator of how active the proteins in the liver are on a given day. Low levels typically indicate disease, while high levels can result from drinking alcohol and/or taking other medications that affect blood clotting.

● Gamma glutamyl transpeptidase (GGT) – This test measures the concentration of enzymes in bile that help break down fats, and can be used to diagnose conditions like liver disease, gallbladder disease, or even pancreatic cancer. Higher levels typically indicate diseases associated with these organs, while lower levels generally do not indicate any specific problems. For more information on blood tests, you can read our comprehensive guide.

Keep in mind that some laboratories may have slightly different standards for testing; your doctor will let you know what is considered a “normal” result for the facility where he or she works. If you have any questions about your test results, feel free to contact your doctor or the laboratory where your tests were run. And remember: no one test can tell you everything about your liver function; in order to understand what’s going on, you will likely need a panel of tests.