What is AST?
Liver Health

What is AST?

Written by

Lauren Dobischok
29 December, 2022

Medically checked article All HOMED-IQ content is reviewed by medical specialists

Aspartate aminotransferase (AST) is an enzyme that is found in the liver, muscles, heart, and blood. When cells that contain AST are inflamed or damaged, AST is released into the blood. This means that elevated AST in the blood can indicate damage to the liver, or other organs such as the heart or kidneys. An AST test can be used to diagnose liver disease, along with other biomarkers like ALT and Gamma GT.

What is AST?

AST is an enzyme that plays a role in amino acid metabolism, catalyzing a reaction between aspartate and glutamate. AST is found in liver, heart, brain, muscle, kidney, and skeletal muscle cells (Sparling, 2016). If these cells are damaged, AST is released into the blood. AST is one of the biomarkers commonly tested to check for liver disease

What are normal AST values?

Normal AST levels are different in men and women. They are:

  • Less than 35 units per litre (< 35 u/L) in women
  • Less than 50 units per litre (< 50 u/L) in men

Normal values for AST can vary slightly between laboratories. An elevated AST does not always mean liver damage- it can also be caused by exercise, pregnancy, surgery, burns, or drug and alcohol use (MedlinePlus, 2022). 

Symptoms of high AST 

High AST can be caused by liver disease. Symptoms of liver disease include:

  • Fatigue
  • Lowered appetite
  • Nausea/vomiting
  • Dark- colored urine
  • Light-colored stools
  • Distended abdomen
  • Jaundice (yellowing of skin or whites of eyes)
  • Frequent itching

Source: MedlinePlus, 2022

How do you measure your AST level?

AST can be measured using a blood test. This can be done at a doctor’s office, blood collection center, or using a home test.

What does the result of an AST test mean?

AST is usually examined with several other biomarkers to check for liver damage. Elevated AST could indicate damage to the liver, liver disease, or another condition, such as heart problems or pancreatitis. If your test result indicates that your ALT is high, speak to your doctor about the potential cause or if more testing is needed.

Why is it important to measure AST?

An AST test is usually a part of a routine blood test for liver health. Testing AST is important in diagnosing or monitoring liver damage. Would you like to check other key biomarkers for liver health from home? Try Homed-IQ’s Liver and Kidney Function Test.


AST Test. (2022). https://medlineplus.gov/lab-tests/ast-test/

Sparling, D. W. (2016). Ecotoxicology Essentials: Environmental Contaminants and Their Biological Effects on Animals and Plants (1st ed.). Academic Press.

About the author

Lauren Dobischok

Lauren is a health scientist and science communicator currently living in the Netherlands. Originally from Canada, she completed a Research Master’s in Health Sciences at the Netherlands Institute of Health Sciences at Erasmus University Rotterdam (NIHES) with a specialisation in epidemiology. Prior to her master’s degree, she completed a Bachelor’s degree in Health Sciences at Simon Fraser University. With a background in public health, her goal is to create accurate scientific content that is easy to understand and empowers people to make informed decisions. Within Homed-IQ, Lauren works as a Product Developer and Content Lead, working closely with physicians and scientists on medical devices for Homed-IQ’s new products and written communications.