Blood Test: Alanine Aminotransferase (ALT, or SGPT)

Blood Test: Alanine Aminotransferase (ALT, or SGPT)

What It Is

An alanine aminotransferase (ALT) test is often part of an initial screening for liver disease.

The liver plays several important roles: It stores fuel from food, makes proteins, and helps remove toxins from the body. The liver also makes bile, a fluid that helps in digestion. Proteins called enzymes help the liver build and break down proteins. ALT (or SGPT, which stands for serum glutamic-pyruvic transaminase) is one of these enzymes. It's found in particularly large amounts in the liver and plays an important role in metabolism, the process that converts food into energy.

Normally, ALT is found inside liver cells. But if the liver is inflamed or injured, ALT is released into the bloodstream. Measuring blood levels of ALT can give doctors important information about how well the liver is functioning and whether a disease, drug, or other problem is affecting it.

Why It's Done

The ALT test may be ordered if your child is experiencing symptoms of liver disease, including jaundice (yellowish skin or eyes), dark urine, nausea, vomiting, or abdominal pain. It also might be ordered to help diagnose infections of the liver such as viral hepatitis (ALT levels are high with acute hepatitis) or to monitor patients taking medications that cause liver-related side effects.

The ALT test is often performed as part of a full hepatic function panel that includes other liver enzyme tests. Looking at ALT levels along with those of other liver enzymes — such as aspartate aminotransferase (AST) and alkaline phosphatase (ALP) — can give doctors more specific information about liver problems.

Preparation

No special preparations are needed for this test. You should tell your doctor about any medications your child is taking because certain drugs might alter the test results.

On the day of the test, having your child wear a short-sleeve shirt can make things faster and easier for the technician who will be drawing the blood.

The Procedure

A health professional will usually draw the blood from a vein. For an infant, the blood may be obtained by puncturing the heel with a small needle (lancet). If the blood is being drawn from a vein, the skin surface is cleaned with antiseptic, and an elastic band (tourniquet) is placed around the upper arm to apply pressure and cause the veins to swell with blood. A needle is inserted into a vein (usually in the arm inside of the elbow or on the back of the hand) and blood is withdrawn and collected in a vial or syringe.

After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. Collecting blood for this test will only take a few minutes.

drawing_blood

heel_prick_illustration

What to Expect

Either method (heel or vein withdrawal) of collecting a sample of blood is only temporarily uncomfortable and can feel like a quick pinprick. Afterward, there may be some mild bruising, which should go away in a few days.

Getting the Results

The blood sample will be processed by a machine. The results are usually reported after a few hours or the next day.

If the results seem to point to liver damage or disease, further testing may be necessary to determine what's causing the problem and how to treat it.

Risks

The ALT test is considered a safe procedure. However, as with many medical tests, some problems can occur with having blood drawn, such as:

Helping Your Child

Having a blood test is relatively painless. Still, many kids are afraid of needles. Explaining the test in terms your child can understand might help ease some of the fear.

Allow your child to ask the technician any questions he or she might have. Tell your child to try to relax and stay still during the procedure, as tensing muscles and moving can make it harder and more painful to draw blood. It also may help if your child looks away when the needle is being inserted into the skin.

If You Have Questions

If you have questions about the ALT test, speak with your doctor.

Reviewed by: Steven Dowshen, MD
Date reviewed: February 2011





Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

© 1995-2014 The Nemours Foundation/KidsHealth. All rights reserved.





Bookmark and Share

Related Resources
OrganizationAmerican Medical Association (AMA) The AMA has made a commitment to medicine by making doctors more accessible to their patients. Contact the AMA at: American Medical Association
515 N. State St.
Chicago, IL 60610
(312) 464-5000
Web SiteNeonatal Jaundice This Web site contains information about jaundice, treatment options, and links.
OrganizationAmerican Academy of Pediatrics (AAP) The AAP is committed to the health and well-being of infants, adolescents, and young adults. The website offers news articles and tips on health for families.
Web SiteAmerican Liver Foundation This nonprofit organization promotes liver health and disease prevention.
Related Articles
Blood Test: Aspartate Aminotransferase (AST, or SGOT) An aspartate aminotransferase (AST) blood test is often part of an initial screening for liver disease.
Blood Test: Comprehensive Metabolic Panel This group of blood tests provides doctors with clues about how the body is working. Find out why doctors do these tests and what's involved for teens.
Blood Test: Hepatic (Liver) Function Panel Liver function tests can help doctors determine if the liver has been damaged. They also can help diagnose viral infections (such as hepatitis or mononucleosis) and monitor medications that can cause liver-related side effects.
Basic Blood Chemistry Tests Doctors order basic blood chemistry tests to assess a wide range of conditions and the function of organs.
Blood Test (Video) This video shows what it's like to get a blood test.
Hepatitis Hepatitis is most commonly caused by one of three viruses. In its early stages, hepatitis may cause flu-like symptoms.
Getting a Blood Test (Video) A blood test might sound scary, but it usually takes less than a minute. Watch what happens in this video for kids.
iGrow iGrow
Sign up for our parent enewsletter