Aspartate aminotransferase (AST)

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Latest Edit: Iva Lloyd, ND 2021-08-24 (EDT)

See Also Lab Tests

Aspartate aminotransferase, also known as AST or SGOT, is the enzyme that catalyzes the conversion of the amino acid L-asparate and α-keto-glutarate into oxaloacetate and L-glutamate., hence the older name SGOT or serum glutamate-oxalocetate tranferase. This test is often used to evaluate coronary artery occlusive disease or suspected hepatocellular diseases.[1], [2]


  • AST is an enzyme found in cells throughout the body, but mostly in the heart and liver, and to a lesser extent in the kidneys and muscles. AST levels increase when liver cells and/or heart muscle cells and/or skeletal muscle cells are damaged.
  • AST is functionally similar to ALT yet it levels do not increase as much in response to liver dysfunction.
  • AST is more specific for the detection of cardiovascular disease.
  • AST levels in the blood typically increase within 12 hours of cellular damage and remain elevated for about 5 days.

Patient Preparation

Fasting is not required for this test.

  • Factors which can cause increased levels:
  • exercise.
  • Drugs: antihypertensives, cholinergic agents, coumarin-type anticoagulants, digitalis preparations, erythromycin, isoniazid, methyldopa, oral contraceptives, opiates, salicylates, hepatotoxic medications, and verapamil.
  • Factors which can cause decreased levels:

Clinical Implications

Ranges:' The following are the reference ranges for this lab. However, lab ranges can vary by laboratory and country. [2]

Standard U.S. Units (U/L) Standard International Units (U/L)
Conventional Laboratory Range 0 - 40 0 - 40
Optimal Range 10 - 30 10 - 30
Alarm Ranges > 100 > 100

High levels indicate:

  • Liver Diseases
  • Skeletal Muscle Disease
  • Skeletal muscle trauma, such as extreme exercise or weight training
  • Recent surgery
  • Multiple traumas
  • Severe, deep burns
  • Progressive muscular dystrophy
  • Recent convulsions
  • Heat stroke
  • Primary muscle diseases, such as myopathy or myositis
  • Other Diseases

Low levels indicate

Associated Tests


  1. Pagana Kathleen D, Pagana Timothy J (2006) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby.
  2. 2.0 2.1 Weatherby Dicken, Ferguson Scott (2002) Blood Chemistry and CBC Analysis: Clinical Laboratory Testing from a Functional Perspective, Bear Mountain.