Physicians use liver function tests to measure how well the liver is functioning as well as to indicate the presence of a disease and manage liver diseases. MayoClinic.com notes that some of the things liver function tests look at include proteins such as albumin and bilirubin and enzymes including alanine transaminase, aspartate transaminase and alkaline phosphatase. Elevated levels can indicate a variety of problems.
Medications
Some medications can raise levels of the liver enzymes alanine transaminase and aspartate transaminase. MayoClinic.com cites drugs prescribed for high blood pressure and cholesterol as well as an overdose of acetaminophen among medications that can raise levels. Increased levels of these enzymes indicate an acute condition of liver inflammation according to the American Association for Clinical Chemistry. This condition is usually temporary.
Hepatitis
Hepatitis B and C can also cause an increase in liver enzymes, particularly in chronic sufferers of these diseases. The American Academy of Family Physicians explains that since the hepatitis virus kills liver cells that produce liver enzymes, the liver function tests of a small subset of patients with hepatitis may appear normal with normal levels of enzymes. Acute infections of viral hepatitis will, however, cause large increases in levels of liver function tests.
Obesity
Obese patients may have elevated liver function tests. Regarding obesity, the American Academy of Family Physicians states that overweight individuals may have more fat in their livers and this increases the amounts of the enzymes aspartate transaminase and alanine transaminase.
Alcohol-related Conditions
Chronic drinking damages the liver and can result in several conditions that can raise levels of liver enzymes and the results of function tests. In alcoholic liver disease, the amount of aspartate aminotransferase is greatly increased. The American Academy of Family Physicians notes that the raised levels of this enzyme are the result of chronic alcoholism which reduces the amount of vitamin B that the liver needs to function normally, and destroys liver cells. Another alcohol-related condition called alcoholic hepatitis raises aspartate transaminase enzyme levels, though not as much as alcoholic liver disease.
Cancer
Cancer of the liver, called hepatocellular carcinoma, can cause elevated liver function tests. The American Association of Clinical Chemistry notes that liver cancer can especially increase levels of the enzyme alkaline phosphatase. Levels of alanine aminotransferase and aspartate aminotransferase can also be somewhat higher than normal.
The American Association of Clinical Chemistry adds that test results are unique to each patient. Many different liver function tests are taken and evaluated together to interpret results.
