Alanine transaminase (ALT) blood test
SGPT; Serum glutamate pyruvate transaminase; Alanine transaminase; Alanine aminotransferaseThe alanine transaminase (ALT) blood test measures the level of the enzyme ALT in the blood.
Enzyme
Enzymes are complex proteins that cause a specific chemical change. For example, they can help break down the foods we eat so the body can use them....
How the Test is Performed
A blood sample is needed.
Blood sample
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
No special preparation is needed.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
ALT is an enzyme found in a high level in the liver. An enzyme is a protein that causes a specific chemical change in the body.
Injury to the liver results in release of ALT into the blood.
This test is mainly done along with other tests (such as AST, ALP, and bilirubin) to diagnose and monitor liver disease.
Normal Results
The normal range is 4 to 36 U/L.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
An increased ALT level is often a sign of liver disease. Liver disease is even more likely when the levels of substances checked by other liver blood tests have also increased.
Liver blood tests
Liver function tests are common tests that are used to see how well the liver is working. Tests include:AlbuminAlpha-1 antitrypsinAlkaline phosphata...
An increased ALT level may be due to any of the following:
- Scarring of the liver (cirrhosis)
Cirrhosis
Cirrhosis is scarring of the liver and poor liver function. It is the last stage of chronic liver disease.
ImageRead Article Now Book Mark Article - Death of liver tissue
- Swollen and inflamed liver (hepatitis)
Hepatitis
Hepatitis is swelling and inflammation of the liver.
ImageRead Article Now Book Mark Article - Too much iron in the body (hemochromatosis)
Hemochromatosis
Hemochromatosis is a condition in which there is too much iron in the body. It is also called iron overload.
ImageRead Article Now Book Mark Article - Too much fat in the liver (fatty liver)
- Lack of blood flow to the liver (liver ischemia)
- Liver tumor or cancer
- Use of drugs that are toxic to the liver
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Mononucleosis ("mono")
Mononucleosis
Mononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.
ImageRead Article Now Book Mark Article - Swollen and inflamed pancreas (pancreatitis)
Risks
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood collecting under the skin)
- Infection (a slight risk any time the skin is broken)
References
Daniels L, Khalili M, Goldstein E, Bluth MH, Bowne WB, Pincus MR. Evaluation of liver function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 22.
Pratt DS. Liver chemistry and function tests. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 73.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 2/28/2023
Reviewed By: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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