Aspartate aminotransferase (AST)

AST is an enzyme in the liver and other organs that helps process amino acids. High levels in blood tests often indicate liver damage or heart issues.

📋 About This Biomarker

Aspartate aminotransferase (AST) is an enzyme found in the liver and other organs like the heart and muscles. Its main job is to help with the metabolism of amino acids, which are the building blocks of proteins in the body.

In medical tests, AST is mostly used to check for liver damage or disease. When the liver is injured or inflamed, AST leaks into the bloodstream, causing higher levels in blood tests. This makes AST a useful indicator for conditions like hepatitis (liver inflammation), cirrhosis (chronic liver damage), and sometimes heart problems or muscle injuries.

⚠️ What Affects It

Aspartate aminotransferase (AST) levels in the body can be influenced by several factors. It is primarily found in liver cells (hepatocytes), so liver damage or diseases like hepatitis, cirrhosis, or fatty liver disease can cause AST levels to rise as liver cells release AST into the bloodstream. AST is also present in heart muscle cells, so conditions such as heart attacks or cardiac issues that damage heart tissue can elevate AST levels. Additionally, AST is found in skeletal muscles, so injuries or trauma to muscles can also increase AST levels due to muscle cell damage. Certain medications, alcohol abuse, toxins, viral infections, and autoimmune hepatitis are other factors that can affect AST levels by causing stress or damage to liver cells. Monitoring AST levels helps healthcare providers assess liver and heart health, diagnose specific conditions, and evaluate the impact of medications or treatments.

📊 Understanding Your Results (U/L)

Low
Low levels of aspartate aminotransferase (AST) in the blood are less common and can be influenced by several factors. One reason for low AST levels is severe malnutrition or deficiencies in vitamin B6, which is necessary for AST activity. In some cases of severe liver disease, such as advanced cirrhosis or end-stage liver failure, AST production may be impaired, resulting in lower enzyme levels. Rare genetic conditions affecting AST synthesis or function can also lead to chronically low enzyme levels. Certain medications, especially those affecting liver function or metabolism, may suppress AST production or release. Additionally, individuals undergoing hemodialysis for kidney failure may have lower AST levels due to removal of the enzyme during dialysis. Low AST levels are considered in the context of other liver function tests and clinical findings to understand their significance. While low AST levels alone may not indicate a specific disease, they can provide clues about underlying nutritional deficiencies, liver dysfunction, or medication effects.
Optimal
Normal levels of aspartate aminotransferase (AST) in the blood typically indicate that the liver, heart, and other tissues where AST is found are functioning normally. AST levels vary depending on the laboratory and the method used for testing, but generally, they fall within a specific range considered normal for healthy individuals. In clinical practice, normal AST levels are important for assessing overall health and diagnosing conditions affecting the liver and heart. AST is primarily found in liver cells (hepatocytes) and heart muscle cells, so normal levels reflect these organs' health and function. When AST levels are within the normal range, it suggests that these tissues are not significantly damaged or inflamed.
High (> 35 U/L)
High levels of aspartate aminotransferase (AST) in the blood usually indicate damage or inflammation in tissues where AST is normally found, such as the liver, heart, or muscles. In the liver, AST can increase due to conditions like hepatitis (liver inflammation), cirrhosis (liver scarring), or fatty liver disease. Heart conditions such as a heart attack (myocardial infarction) can also elevate AST levels when heart muscle cells are damaged. Additionally, AST levels may rise with muscle injury caused by trauma, intense exercise, or conditions like rhabdomyolysis (muscle breakdown). Certain medications, toxins, or alcohol can temporarily increase AST levels by affecting liver or muscle function.
Also known as: AST