Contributed by – Healthians Team
What is the ALT test?
The ALT test is a simple blood test that measures the levels of alanine transaminase (ALT) enzymes that your liver releases in response to damage or disease. The test is a part of a group of liver function tests called a liver panel. ALT blood test used to be earlier called serum glutamic-pyruvic transaminase, or SGPT.
ALT is an enzyme (protein) found mostly in the liver. It is predominantly used by your body to metabolize protein. In healthy individuals, its levels in the blood are low. However, when the liver is injured or damaged for any reason, it puts more ALT into your bloodstream, and your levels rise. Elevated levels of this enzyme can therefore indicate liver disease.
An ALT blood test can help to indicate conditions such as jaundice, a condition that causes your skin and eyes to turn yellow. The test is highly effective in detecting damage due to hepatitis (inflammation of the liver) or as a result of non-steroidal anti-inflammatory drugs (NSAIDs) like Aspirin, ibuprofen, and naproxen sodium that are toxic to the liver.
Who should get the test?
Get yourself tested if you have any persistent signs or symptoms as below:
- yellowish discolouration of skin or eyes (jaundice)
- abdominal pain and swelling in the belly
- nausea and vomiting
- extreme tiredness
- disorientation (confusion and uncertainty)
- loss of appetite
- unusually itchy skin
- changed colour of urine and stool
Besides, there are certain risk factors of liver disease and the doctor may suggest having this test if you:
- are exposed to hepatitis A, B or C
- consuming excessive alcohol
- have a family history of liver disease
- are obese
- have diabetes
- have pre-existing medical conditions
- are taking certain medications
That said, regardless of the cause of elevated ALT levels, it is important to work with your doctor to find and address the underlying cause.
Why is the ALT test needed?
The value of ALT level can indicate not only the cause of liver disease but also its severity. Your doctor may recommend the ALT test:
- To measure your liver enzymes and identify if you have liver disease.
- To check if your liver is damaged due to alcoholism or drugs
- As part of a comprehensive metabolic panel (CMP)when you have a routine health exam.
If you test positive for high levels of liver enzymes, your doctor may compare your ALT results with the levels of another liver enzyme at the same time. This enzyme is called alanine aminotransferase (AST).
What does the ALT test result mean?
Normal Result:
Normal value ranges are:
Males: 29 to 33 units per litre (IU/L)
Females: 19 to 25 IU/L
What Abnormal Results Mean
Mild, asymptomatic elevations (less than five times the upper limit of normal) of ALT are common. However, very high levels of alanine transaminase (more than 10 times normal) usually indicate acute hepatitis, sometimes viral hepatitis infection.
How is the test done?
ALT testing is done by drawing a blood sample from a vein that can technically be done without any special preparation. You may be required to avoid eating or drinking for several hours or overnight before the test. Certain drugs can change the protein levels in your blood. Therefore, your health care provider may instruct you to stop taking certain over-the-counter (OTC) medications that affect the test. It’s a good idea to increase your consumption of water a day before your blood draw. When the body is properly hydrated, veins allow easier access.
