Blood Test Detects Tumor DNA to Guide Advanced Cancer Treatment

Liver function tests are a group of blood tests that provide important information about the health and functioning of your liver. The liver is a vital organ that performs many essential tasks including filtering toxins from the blood, producing bile to help digest fats, storing vitamins and minerals, and making proteins needed for blood clotting. When the liver is damaged or diseased, it may release certain enzymes and proteins into the bloodstream or fail to produce substances it normally makes. Liver function tests measure the levels of these substances to help detect liver problems.

Common components of liver function tests include measurements of enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which are released when liver cells are damaged. The tests also measure alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT), which can indicate problems with bile flow. Additionally, the tests evaluate bilirubin levels, a yellow pigment produced when red blood cells break down, and protein levels including albumin and total protein, which reflect the liver's ability to synthesize proteins.

Your doctor may order liver function tests for several reasons. They can be used to screen for liver infections such as hepatitis, monitor the progression of liver disease, check for side effects of medications that might affect the liver, or evaluate symptoms such as jaundice, abdominal pain, nausea, or unexplained fatigue. The tests are also useful for monitoring treatment effectiveness in people already diagnosed with liver disease.

Preparing for liver function tests is usually straightforward. In most cases, you may need to fast for 8 to 12 hours before the blood sample is taken, though this depends on your doctor's instructions. The blood draw itself is a quick procedure performed at a laboratory or medical office. Results are typically available within a few days, and your healthcare provider will interpret them in the context of your medical history, symptoms, and other test results to determine if further evaluation or treatment is needed.