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Normal (AST) Aspartate Aminotransferase level in the blood

Blood test
Normal (AST) Aspartate Aminotransferase level in the blood
Last update: 25/03/2020

What is the normal level of AST in the blood?

Adult Men: 5 to 50 U/L
Adult Women: 5 to 35 U/L
Neonate: 25 to 75 U/L
Baby: 15 to 60 U/L

In the International System of Units (SI), the AST in the blood is measured in ukat/l. The normal AST levels in the blood in the SI are:

Adult men: 0.08 to 0.83 ukat/L
Adult women: 0.08 to 0.58 ukat/L
Neonate: 0.42 to 1.25 ukat/L
Baby: 0.25 to 1 ukat/L

Why normal levels can differ across different labs?

Each laboratory must establish its own normal ranges for AST (aspartate aminotransferase) in the blood. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal levels, according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.

Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.

What is the role of AST Aspartate Aminotransferase?

The AST (Aspartate Aminotransferase), formerly named glutamate oxaloacetate transaminase (GOT), is an enzyme of the transaminase group. The AST plays a critical role in amino acid and carbohydrate metabolism.

The AST is found mostly in the liver, but it is also present in various parts of the body such as:

  • Heart
  • Muscles
  • Kidney
  • Brain
  • Red blood cells

The AST is released into the blood when there is a liver injury or damage. The level of AST in the blood increases when there is damage to the liver tissue and cells.

What is the AST blood test for?

The AST (Aspartate Aminotransferase) blood test is used to diagnose liver disorders. It may also indicate cardiac disease.

An increase in the AST is associated with liver cell injury. AST elevation is typically observed in alcoholic liver disease patterns, in patients with hepatitis (inflammation of the liver) or cirrhosis.

The AST is higher after a heart attack and the AST development predict the prognosis of the heart attack.

The AST concentration in the blood is closely related to the ALT (alanine aminotransferase) concentration. Both, the AST transaminase and the ALT transaminase usually increase simultaneously.

The AST/ALT ratio, known as “De Ritis Ratio”, is useful to diagnose different causes of liver damage. AST/ALT ratio of less than 1 is suggestive of limited liver damage and it may be observed in inflammatory liver diseases. AST/ALT ratio higher than 1 is suggestive of a severe hepatopathy related to liver necrosis.

Low AST concentration in the blood is rare and it may be a consequence of vitamin deficiency, for example, vitamin B6 deficiency.

Where can I find more information about AST in the blood?

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Which values are considered a normal AST level in the blood?

The following values are considered to be normal values:

IMPORTANT: These levels are expressed in U/L. They are an example of a healthy man of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

AST Aspartate Aminotransferase
5 U/L6 U/L7 U/L8 U/L9 U/L10 U/L11 U/L12 U/L
13 U/L14 U/L15 U/L16 U/L17 U/L18 U/L19 U/L20 U/L
21 U/L22 U/L23 U/L24 U/L25 U/L26 U/L27 U/L28 U/L
29 U/L30 U/L31 U/L32 U/L33 U/L34 U/L35 U/L36 U/L
37 U/L38 U/L39 U/L40 U/L41 U/L42 U/L43 U/L44 U/L
45 U/L46 U/L47 U/L48 U/L49 U/L50 U/L  
Medically reviewed by Javier Muga Bustamante Ph.D. on 25/03/2020


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  • Thomas L. Alanine aminotransferase (ALT), Aspartate aminotransferase (AST). In:Thomas L, ed. Clinical laboratory diagnostics. Use and assessment of clinical laboratory results. Frankfurt/Main: TH-Books Verlagsgesellschaft, 1998:55-65 ISBN: 9783980521543.
  • Thomas L, Müller M, Schumann G et al. Consensus of DGKL and VDGH for interim reference intervals on enzymes in serum. J Lab Med 2005;29:301-08.
  • Painter PC, Cope JY, Smith JL. Chapter 50. Reference information for the clinical laboratory. In: Burtis CA, Ashwood ER, eds. Tietz textbook of clinical chemistry. Philadelphia:WB Saunders Company, 1999;1802pp. ISBN 9780721656106.
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  • Severity grading in drug induced liver injury. U.S. National Library of Medicine. Available on:

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