Alanine Aminotransferase (ALT): Results

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Results

An alanine aminotransferase (ALT) test measures the amount of this enzyme in the blood. Results are usually available within 12 hours.

Normal

Normal results may vary from lab to lab.

High values

Very high levels of ALT may be caused by:

• Recent or severe liver damage, such as viral hepatitis.
• Lead poisoning.
• Drug reactions.
• Exposure to carbon tetrachloride.
• Decay of a large tumor (necrosis).
• Shock.

Mildly or moderately high ALT levels may be caused by:

• Mononucleosis.
• Hepatitis. The ALT level in a person with hepatitis can be 20 times the normal value.
• Alcohol abuse. People who drink excessive amounts of alcohol and take acetaminophen (such as Tylenol) can have high ALT blood levels.
• Mildly elevated levels of ALT may occur in people who are growing quickly, especially young children.

Slightly high levels ALT levels may be caused by:

• Fatty deposits in the liver.
• Many medicines, such as statins, antibiotics, chemotherapy, aspirin, narcotics, and barbiturates.
• Long-term (chronic) diseases that affect the liver, such as cirrhosis.

Last updated:	January 02, 2008
Author:	Maria G. Essig, MS, ELS
Reviewed By:	Kathleen Romito, MD - Family Medicine, Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer