Alanine Aminotransferase Test (ALT) – Why am I having this test?
Alanine aminotransferase test is used to evaluate a person for liver disease. It may also be used to monitor the treatment of a person who has liver disease.
High levels of ALT may indicate that there is a liver problem or that a treatment for a liver problem is not working. A health care provider may order an ALT test along with other tests.
What is being tested?
This test measures the level of alanine aminotransferase in the blood. Alanine aminotransferase is an enzyme that is found mainly in the liver but also in the kidneys, the heart, and muscles that are connected to the skeleton (skeletal muscles). Under normal conditions, ALT levels in the blood are low. High (elevated) ALT levels may be caused by:
- Damage to the liver. This is the main cause of an abnormality.
- Damage to the kidneys, the heart, or skeletal muscles.
- Certain medicines.
What kind of sample is taken?
A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.
How are the results reported?
Your test results will be reported as a range of values. Your health care provider will compare your results to normal values that were established after testing a large group of people (reference values). Reference values may vary among labs and hospitals. For this test, common reference values are:
- Adult, female: 4–19 units/L.
- Adult, male: 7–30 units/L.
- Children:
- Younger than 12 months: 0–54 units/L.
- 1–2 years old: 3–37 units/L.
- 2–8 years old: 3–30 units/L.
- 8–16 years old: 3–28 units/L.
What do the results mean?
Test results that are significantly elevated may indicate:
- Hepatitis.
- Liver tissue death (hepatic necrosis).
- Decreased blood flow to the liver (hepatic ischemia).
Test results that are moderately elevated may indicate:
- Cirrhosis.
- Liver tumor.
- Medicines that are causing strain on the liver.
- Severe burns.
Test results that are mildly elevated may indicate:
- Pancreatitis.
- Heart attack.
- Infectious mononucleosis.
- Shock.
Talk with your health care provider about what your results mean.
Questions to ask your health care provider
Ask your health care provider, or the department that is doing the test:
- When will my results be ready?
- How will I get my results?
- What are my treatment options?
- What other tests do I need?
- What are my next steps?
Summary
- An alanine aminotransferase (ALT) test is used to evaluate a person for liver disease.
- High (elevated) ALT levels are commonly caused by medicines or damage to the liver.
- Talk with your health care provider about your results, your treatment options, and whether you need more tests.
