A liver function test is a group of blood tests that physicians use to evaluate liver function. Some tests included in the liver function panel include albumin, ALP, AST, ALT, Gamma-glutamyl transpeptidase, prothrombin time, serum bilirubin, urine bilirubin and alpha-1 antitrypsin. Liver function tests help physicians detect and evaluate liver damage or disease; abnormal results are not uncommon.
Function
There are many reasons why a physician will order a liver panel. People who have a history of, or who have been exposed to, hepatitis viruses might have a liver function study, as well as people who are heavy drinkers. People with a family history of liver disease may also have this test in order to monitor for early signs of the disease. If a person experiences weakness, fatigue, nausea, vomiting, yellowing of the skin or eyes known as jaundice, dark urine or a light stool and abdominal pain or swelling, a physician may order a liver function test as part of the diagnostic tests performed, according to Lab Tests Online.
Testing
A liver function test is a blood test with little if any risk involved. A technician will have the patient take a seat and will tie a tourniquet above the site where the blood is to be drawn. Once the technician finds the vein, he swabs the vein with alcohol to avoid introducing bacteria into the site. He then inserts a small needle into the vein and collects a sample. Once the sample is collected, the technician removes the tourniquet and applies a bandage. The patient may need to sit for a moment if he feels lightheaded, but then can return to normal activity.
Abnormal Results
A liver function panel will not diagnose a specific condition. Physicians use this information in conjunction with other tests in order to diagnose a patient. Acute liver damage may cause bilirubin, and the liver enzymes, ALT and AST to be elevated, with ALP only moderately increased; chronic forms of liver disease may show only a slight increase or none at all. Alcoholic hepatitis will often show an AST level that is twice the level of ALT. All of these test results are subjective when taken out of context. In some cases, the increased levels are transient, and on another day, levels have returned to normal. People can unknowingly alter liver function tests by drinking alcohol or eating certain foods, according to MayoClinic.com.
Causes
A liver function study can help physicians diagnose viral infections, such as hepatitis A, B or C, as well as alcohol abuse. Lab Tests Online explains that other possible causes of abnormal results include liver cancer, chronic liver disease, Wilson's disease, drug abuse and toxins.
Follow-Up
Physicians may choose to do imaging studies such as magnetic resonance imaging or computerized tomography as part of the follow-up to the test. The physician may also want to collect a sample of the liver tissue, a procedure known as a biopsy, in order to confirm a suspected diagnosis.
