The liver function panel, also known as the hepatic function panel, includes seven tests performed on the same blood sample. The hepatic function panel components include ALT, AST, ALP, total bilirubin, direct bilirubin, total protein, and albumin.
Hepatic Function Testing
Doctors order the liver function panel when they suspect liver dysfunction. Some signs and symptoms of liver problems include dark urine, nausea, vomiting, loss of appetite, diarrhea, jaundice (yellowing of the skin), light-colored bowel movements, bloody bowel movements, abdominal swelling, fatigue, unusual weight changes, and pain in the abdomen. This test is also useful in people with alcoholism and those who may have been exposed to one of the hepatitis viruses.
Alanine Aminotransferase (ALT)
ALT is one of the hepatic function panel components doctors use to determine if there is a problem with the liver. This is one of the most important and specific tests for detecting injury to the liver. In addition to the liver, this enzyme is also found in the pancreas, kidneys, muscles, and heart. Another name for ALT is serum glutamic pyruvic transaminase (SGPT). When liver damage occurs, the organ releases ALT, causing levels of this enzyme to increase.
Aspartate Transaminase (AST)
Aspartate transaminase, also known as serum glutamic-oxaloacetic transaminase, alerts doctors to liver damage caused by hepatitis, alcoholism, and other diseases. Lab professionals compare levels of this enzyme with levels of ALT and other hepatic function panel components. This compare allows doctors to make more specific diagnoses than if they used AST levels alone. In addition to testing for liver dysfunction caused by disease, this test can detect high AST levels caused by certain medications.
Alkaline Phosphatase (ALP)
Alkaline phosphatase, another enzyme, is found in the liver, intestines, bones, kidneys, and other organs. Bone growth causes children and teenagers to have higher levels of this enzyme than adults who have already stopped growing. Viral infections, blockages of the bile ducts, and diseases of the liver also cause elevated ALP levels.
The hepatic function panel includes tests for total bilirubin and direct bilirubin. Bilirubin occurs normally in the blood as a waste product created the breakdown of erythrocytes (red blood cells). The liver helps to excrete this waste product from the body, but a decline in liver function allows it to build up in the blood. When bilirubin levels rise, the skin turns yellow (jaundiced) as a result. Total bilirubin measures all of the bilirubin in the blood, while direct bilirubin only measures the bilirubin that has attached to other chemicals after going through the liver.
Total Protein & Albumin
A liver that functions normally helps with the production of protein in the body. Protein helps build strong muscles and other tissues. When liver function declines, this organ does not produce protein as well as it should. This causes protein levels to decrease. Albumin, the major protein made by the liver, also decreases in the blood. The hepatic function panel measures both total protein and albumin to determine if there is a problem with protein production in the liver.