What is the ALT test?

This blood test measures an enzyme called alanine transaminase (ALT). Enzymes are chemicals that help the cells of your body work. ALT is an enzyme made in the liver. It is released into the blood when tissues are damaged.

This enzyme is also called serum glutamic-pyruvic transaminase, or SGPT.

Why is this test done?

The ALT test checks for and measures damage to the liver. It is also done to check medical treatments that may affect the liver.

How do I prepare for this test?

  • You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Ask your provider before stopping any of your regular medicines.
  • Talk to your healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your arm with a needle. The blood is collected in tubes and sent to a lab.

Ask your healthcare provider when and how you will get the result of the test.

What does the test result mean?

Some of the reasons your ALT level may be much higher than normal (up to 50 times the upper limit of normal) are:

  • You have liver damage from an acute viral infection such as hepatitis.
  • You have liver damage caused by medicines you have taken.

Your ALT levels may be higher than normal also if:

  • You drink too much alcohol.
  • You have mononucleosis.
  • You have liver or gallbladder disease, such as gallstones, liver cancer, or liver failure.
  • You have a muscle injury.
  • You are taking a medicine that affects the test result.

No medical problems are known to cause an ALT level that is lower than normal. Sometimes the test result may be lower than normal but it does not mean there is a problem.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about the results and ask questions, such as:

  • If you need more tests
  • What kind of treatment you might need
  • What lifestyle, diet, or other changes you might need to make
Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth.
Last modified: 2013-10-18
Last reviewed: 2014-02-03
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.

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