Liver function tests check the levels of certain enzymes and proteins in your blood, and 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 dont always indicate liver disease, and your doctor will explain your results and what they mean.
The normal range for liver function tests can vary between different sexes, body sizes, and laboratories. On average, normal ranges are:
- Alanine transaminase (ALT): 0 to 45 IU/L
- Aspartate transaminase (AST): 0 to 35 IU/L
- Alkaline phosphatase (ALP): 30 to 120 IU/L
- Gamma-glutamyltransferase (GGT): 0 to 30 IU/L
- Bilirubin: 2 to 17 micromoles/L
- Prothrombin time (PT): 10.9 to 12.5 seconds
- Albumin: 40 to 60 g/L
- Total proteins: 3 to 8.0 g/dL
Elevated levels of liver enzymes in general signify some form of liver (or hepatic) damage or injury, and they may be elevated acutely (short term) indicating sudden injury to the liver, or they may be elevated chronically (long term) suggesting ongoing liver injury. The most important step in evaluating patients with abnormal liver enzyme levels is to take a thorough history and perform a physical examination.
