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Liver Blood Tests

Liver Blood Test Quick Overview

  • Liver blood tests are designed to show evidence that abnormalities, for example, inflammation, liver cell damage, has or is occurring within the liver.
  • The blood tests most frequently used for liver disease are the aminotransferases (alanine aminotransferase or ALT and aspartate aminotransferase or AST).
  • Normal levels of ALT ranges from about 7-56 units/liter, and 10-40units/liters for AST.
  • Elevated levels of AST and ALT may signify the level of liver damage in a person.
  • Common causes of elevated ALT and AST are
  • Many drugs may cause elevated AST, and ALT and some medications can cause severe damage (for example, acetaminophen [Tylenol liver damage]).
  • Less common causes of abnormal AST and ALT levels are wide ranging (for example, toxins, and autoimmune diseases)
  • People with mild to moderate elevations of AST and ALT with no or few symptoms should follow-up with their doctor for potential underlying causes of elevated AST and/or ALT.
  • Repeated test levels (monitoring) is useful in some patients (for example, viral-caused and Tylenol-caused elevations) to guide therapeutic treatments.
  • Other liver enzymes, although not measured routinely, may add additional information about liver functions.

Aminotransferases (AST, ALT)

Aminotransferases are enzymes (proteins that help speed up chemical reactions in the body) that are found mainly in the liver, but also in other tissues, such as muscles. They are a part of the normal metabolic processes in the liver and are responsible for transferring amino acids (components that build proteins) from one molecule to another. ALT was formerly known as serum glutamic-pyruvic transaminase (SGPT) and AST as serum glutamic-oxaloacetic transaminase (SGPT).

The ALT and AST levels are obtained directly from a blood sample that is sent to the laboratory for measurement. The results are usually available within hours to days and are reported to the ordering doctor for review.

Medically Reviewed by a Doctor on 8/19/2015

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Liver Blood Tests - Causes

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Live Blood Tests - Medications as Cause

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