High and low levels, and what do results mean

An AST blood test measures levels of aspartate aminotransferase (AST) and helps determine liver function. Too much of this enzyme can indicate a problem, such as liver damage.

Aspartate aminotransferase (AST) is an enzyme mostly found in the liver. AST is also present in other parts of the body, including the:

• kidneys
• heart
• muscles

Another name for the AST enzyme is serum glutamic-oxaloacetic transaminase (SGOT).

Most people have low levels of the AST enzyme. Damage to liver cells can cause the release of extra AST into the blood though, leading to higher levels of the enzyme.

After taking a blood test, doctors will classify AST ranges as normal, high, or low. Laboratories may use different testing methods for analyzing samples, so normal ranges can vary between each laboratory.

There is not an exact range for AST levels, as levels can vary among people and still be normal. AST levels can vary depending on factors such as:

• age
• sex
• weight
• race

The measurements for AST levels are typically in units per liter (U/L) or international units per liter (IU/L). On a test result, the laboratory will usually list their specific reference range.

People will need to look at this reference range and discuss with their doctor what their test results mean for them. To understand the results of an AST blood test, a doctor will also look at other enzymes that can indicate a liver problem.

The following table indicates general AST blood test ranges. However, reference ranges can vary slightly among different laboratories.

Results from an AST blood test can help indicate liver health.

If AST levels are high, it may also be a sign of:

• chronic hepatitis
• damage from alcohol
• cholestasis, a decrease in bile flow
• heart, kidney, bone, or muscle damage
• liver cancers
• liver scarring, known as liver cirrhosis

Very high AST levels are usually a sign of progressing liver damage, often due to acute hepatitis.

Low AST levels may indicate:

• vitamin B6 deficiency
• kidney disease
• liver disease
• cirrhosis
• cancer
• autoimmune conditions
• genetic conditions

A doctor may also test levels of alanine aminotransferase (ALT), another liver enzyme. ALT levels occur in higher concentrations in the liver.

If ALT levels are normal but AST levels are high, it could indicate a health problem outside of the liver, or it may be a sign of alcohol-induced liver damage.

Having high levels of AST and no other signs of a problem is not necessarily a cause for concern. People with normal liver function can have high AST levels, which may be due to:

• age
• sex
• race
• certain medications

A person should always discuss any medications or health products they take with a doctor.

Doctors primarily use the AST blood test to check for and assess liver problems, usually alongside other liver tests. The AST protein mainly occurs in the liver and heart. With liver damage, AST can leak from the liver into the bloodstream. When this happens, AST levels in the blood will be higher than normal.

AST also occurs in the brain, heart, kidneys, and muscles. If there is damage in any of these areas, AST levels may also increase.

To rule out issues affecting areas outside the liver, doctors may order a check of the second liver enzyme, ALT, at the same time. If both levels are high, it may indicate a problem with a person’s liver. If only AST levels are high, this may indicate a problem with another organ or system.

People may have an AST test for screening, diagnosis, or monitoring purposes. A doctor may recommend this test if a person:

• has risk factors for liver disease, such as family history, obesity, or diabetes
• has symptoms of a liver problem, such as jaundice, fatigue, or unexplained weight loss
• is undergoing treatment for a liver condition, as an AST blood test can help show how well treatment is working

Alanine aminotransferase (ALT) is an enzyme that mostly occurs in the liver. If there is damage to liver cells, ALT levels in the bloodstream can increase. An ALT test can help indicate liver health, along with other liver enzyme tests.

Healthcare professionals may use both ALT and AST tests to check for the presence of liver enzymes in the blood, as this can give them a clearer idea of overall liver function and health.

Learn more about the ALT test here.

The AST blood test is straightforward and similar to any other blood test. A healthcare professional may take the following steps:

• sit the person down and tie a stretchy band around the upper arm to increase blood flow to that area
• clean the site of the blood draw with an antiseptic wipe
• insert a needle into a vein in the arm to take a blood sample, which may cause people to feel a mild prick or pain
• remove the needle once they have drawn enough blood
• send the blood sample to a laboratory for testing

An AST blood test will usually only take a few minutes in total.

In some cases, people may be able to take an AST test at home. Using an at-home test kit, people will take a blood sample from their fingertip and send the sample to a laboratory. People may receive AST blood test results through the mail, an app, or an online system.

Learn how long it might take to receive blood test results here.

Preparation

People may need to fast for several hours if they are having a combination of liver enzyme tests.

If people are only having an AST blood test, they may not need to fast or prepare in any way.

People will need to let their doctor know if they are taking any medications or supplements, as some may interfere with liver enzyme levels.

As a healthcare professional will be taking blood from the arm, it may be helpful to wear short sleeves during the test.

As with any blood test, an AST blood test has very few risks. It is rare to experience any severe side effects, but people may have some mild bruising or discomfort in the area at the site of the blood draw.

A healthcare professional will place a Band-Aid or bandage on the arm to stop any bleeding.

People may want to have something to eat after the test, particularly if they were fasting beforehand. It is safe for people to drive and continue their usual activities after an AST blood test, unless they experience any unusual symptoms.

A doctor may order tests along with an AST blood test or follow-up tests. This is to help ensure proper diagnosis and determine the best course of treatment. These tests may include:

• ALT test: A doctor may order an ALT test alongside an AST test.
• Platelet count: Low platelet levels may indicate HELLP syndrome during pregnancy.
• Coagulation panel: This measures the functioning of clotting-related proteins that the liver produces.
• Complete metabolic panel: This assesses how well the kidneys and liver are working and shows levels of electrolytes.
• Bilirubin test: A bilirubin test checks levels of a byproduct created when the liver breaks down red blood cells.
• Glucose test: High or low blood glucose levels may indicate a liver problem.
• Viral testing: This can help doctors check for hepatitis.
• Imaging: A doctor may order images of the liver via ultrasound.

The extent of follow-up testing will depend on a person’s results. A doctor may also take additional blood tests, imaging tests, or a biopsy to identify or rule out any potential conditions relating to abnormal AST levels.

Learn about different types of blood tests here.

An AST blood test, or SGOT test, checks how much AST, a liver enzyme, is present in the blood. High levels of AST in the bloodstream could be a sign of liver damage, or cell damage in another organ such as the heart or kidneys.

Doctors may also take additional tests to check other liver enzymes, such as ALT, to get more information on the health of the liver.

Alanine aminotransferase (ALT) test: Uses and results

The liver makes several enzymes, including alanine aminotransferase, or ALT. These enzymes help break down proteins so that the body can digest them.

Besides helping the liver break down proteins, ALT helps the liver perform its basic functions. Some of these include:

• filtering toxins from the blood
• storing nutrients and iron
• producing bile, which aids digestion

Most ALT that the liver produces stays within the organ. However, when the liver is damaged or inflamed, it may release ALT into the bloodstream.

When this happens, the level of ALT in the blood rises. Therefore, doctors use an ALT blood test to screen for liver disease or damage. Learn more about the test in this article.

Share on PinterestAn ALT test can help a doctor diagnose various liver conditions.

A doctor orders an ALT test to look for problems with liver function. Many people have this test as part of a comprehensive metabolic panel.

The comprehensive metabolic panel is a routine blood test that checks a person’s glucose level, kidney function, and liver function. It is often part of a routine checkup that gives a doctor insight into an individual’s overall health.

Other times, a doctor orders the ALT blood test as part of a series of blood tests called liver panels if they suspect that a person’s liver is damaged or diseased.

Doctors may order liver panels if a person has symptoms of liver disease or damage. Symptoms of liver problems include:

• yellowing of the eyes and skin (jaundice)
• pain in the upper right quadrant of the abdomen
• referred pain in the right shoulder
• easy bleeding or bruising
• intense itching
• pale stools
• swelling in legs or abdomen

These symptoms can indicate liver disease, injury, or another problem that may be affecting the liver.

Medical problems that can cause elevated ALT levels include:

• hepatitis
• nonalcoholic fatty liver disease
• cirrhosis
• celiac disease
• thyroid disorders
• preeclampsia in pregnant or immediately postpartum women
• certain infections, including mononucleosis and sepsis
• Wilson’s disease
• polymyositis
• liver cancer

Certain medications can also cause ALT levels in the blood to be high.

Often, these levels are elevated before symptoms of liver damage occur, making the test useful for people at risk of liver damage.

When a doctor can detect liver damage early, they may be better able to treat it and prevent further injury.

People at risk of liver damage or disease include:

• people with a family history of liver disease
• people who have diabetes
• people who are overweight
• people who consume a lot of alcoholic beverages
• people taking certain medications

Doctors routinely order liver panels to monitor diagnosed liver disease or injury. The results of these tests can show how well the treatment plan is working.

Share on PinterestA doctor can explain the results of an ALT test in detail.

A person with a healthy liver will have an ALT level in the normal range. The normal range can vary from laboratory to laboratory.

According to the Mayo Clinic, the normal range for adult males is 7–55 units per liter. Females may have a lower upper limit normal than males.

Age can also affect results. A person should speak with their doctor about what their results mean.

If a person has results above the normal range, this may indicate liver damage.

Causes of elevated ALT levels include:

• the destruction of liver cells
• a lack of blood flow to the liver
• hepatitis
• cirrhosis, or severe scarring of the liver
• diabetes
• hemochromatosis, or iron buildup
• mononucleosis, an infection usually caused by the Epstein-Barr virus
• a tumor in the liver
• pancreatitis

A person should discuss their results with their doctor, who can say if the numbers returned are within a normal range.

If a person’s results are too low or high, a doctor can help determine the appropriate course of treatment.

People with higher ALT levels often need additional tests to discover the underlying cause of the liver damage and treat it.

An ALT blood test helps determine if a person has liver damage. Uncovering the cause of the problem often requires further testing.

The normal range for results tends to vary among facilities, and a doctor can discuss what the results mean on an individual basis.

Once they know the underlying cause of the liver damage, based on symptoms and test results, the doctor will discuss appropriate treatment options.

Aspartate aminotransferase (AST)

Aspartate aminotransferase (AST) is an enzyme that is found in all cells of the body, but mainly in the cells of the heart and liver, and to a lesser extent in the kidneys and muscles. Normally, AST activity in the blood is very low. When liver or muscle tissue is damaged, it is released into the blood. Thus, AST is an indicator of liver damage.

Synonyms Russian

Serum glutamine-oxaloacetic transaminase, serum glutamate-oxaloacetate transaminase (SGOT), aspartate transaminase, AST/ALT ratio.

Synonyms English

Aspartate aminotransferase.

Test method

UV kinetic test.

Units

U/L (unit per litre).

What biomaterial can be used for research?

Venous, capillary blood.

How to properly prepare for an examination?

• Do not eat for 12 hours before the test.
• Exclude physical and emotional overexertion within 30 minutes prior to the study.
• Do not smoke for 30 minutes before the test.

Study Overview

Aspartate aminotransferase (AST) is an enzyme found in all cells of the body, but primarily in the heart and liver, and to a lesser extent in the kidneys and muscles. In healthy patients, AST activity in the blood is low and the AST norm has low values. When the liver or muscles are damaged, AST is released, and the level of AST in the blood rises. In this regard, the activity of this enzyme is an indicator of liver damage. An analysis for AST is part of the so-called liver tests – studies that diagnose disorders in the liver.

The liver is a vital organ located in the upper right side of the abdomen. It is involved in many important bodily functions – helping with nutrient processing, bile production, the synthesis of many important proteins such as blood clotting factors, and breaking down potentially toxic compounds into harmless substances.

A number of diseases lead to damage to liver cells, which increases the activity of AST.

The most common test for AST is to check if the liver is damaged due to hepatitis, toxic drugs, cirrhosis. However, AST does not always reflect only liver damage; the activity of this enzyme can also increase in diseases of other organs, in particular, in myocardial infarction.

What is research used for?

• To detect liver damage. Typically, an AST test is ordered along with an alanine aminotransferase (ALT) test or as part of a general liver function test. AST and ALT are considered the two most important indicators of liver damage, although ALT is more specific than AST. In some cases, AST is directly compared with ALT and their ratio (AST/ALT) is calculated. It can be used to find out the causes of liver damage.
• Blood AST is often compared with other tests, such as alkaline phosphatase (AP), total protein, and bilirubin, to determine a specific form of liver disease.
• To monitor the effectiveness of the treatment of liver diseases.
• To monitor the health of patients taking medications that are potentially toxic to the liver. If AST activity rises, the patient may be switched to other medications.

When is the test ordered?

• For symptoms of liver disorder:
  • weakness, fatigue,
  • loss of appetite,
  • nausea, vomiting,
  • abdominal pain and bloating,
  • yellowing of the skin and whites of the eyes,
  • dark urine, light stool,
  • itching.

• If there are factors that increase the risk of liver disease:
  • previous hepatitis or recent exposure to hepatitis infection,
  • excessive alcohol consumption,
  • hereditary predisposition to liver diseases,
  • taking drugs that can damage the liver,
  • overweight or diabetic.
  • On a regular basis throughout the treatment process to determine its effectiveness.

What do the results mean?

Reference values ​​(AST norm for men, women and children):

Normally, the activity of AST in the blood is low.

Excessively high AST activity (more than 10 times normal) is usually caused by viral infections. It can also increase significantly as a result of taking drugs or other substances that are toxic to the liver, as well as due to diseases that slow blood flow to the liver (ischemia).

In chronic hepatitis, AST activity usually exceeds the norm by no more than 4 times. It fluctuates between normal and somewhat elevated, so often an analysis is prescribed to determine the degree of the disease. Diseases such as obstruction of the biliary tract, cirrhosis, and some types of liver cancer contribute to a moderate increase in AST. After a heart attack and with muscle damage, AST activity can also increase, usually much more than ALT.

In most liver diseases, ALT activity in the blood is higher than AST activity, so the AST/ALT ratio will be low. However, there are a few exceptions: alcoholic hepatitis, cirrhosis, and muscle damage.

Important notes

• During pregnancy, AST activity may decrease.
• Intramuscular injections of drugs, as well as intense physical activity, increase the activity of AST in the blood.
• In some patients, liver damage and, as a result, an increase in AST activity can be caused by taking dietary supplements. Therefore, it is necessary to inform the attending physician not only about all medications taken, but also about nutritional supplements.

Also recommended

• Alanine aminotransferase (ALT)
• Alkaline phosphatase, total
• Gamma-glutamyl transpeptidase (gamma-GT)
• Serum albumin
• Total protein in whey

Who orders the examination?

Therapist, cardiologist, hepatologist, gastroenterologist, general practitioner, surgeon, pediatrician.

Alanine aminotransferase (ALT, ALT), aspartate aminotransferase (AST, AST) – Biochemical blood test – Deciphering tests online

Alanine aminotransferase (ALT, ALT), aspartate aminotransferase (AST, AST) 9000 3

Liver tests is a set of indicators a biochemical blood test, with which you can evaluate some of the functions of the liver. To assess the degree of damage to liver cells (hepatocytes), it is necessary to pass an analysis to determine the level of certain liver enzymes (proteins) in the blood. Damage to the wall of the hepatocyte entails an increased release of liver enzymes into the blood.

Decipher “Complete blood count”
Decipher “Complete urinalysis”

Aminotransferases are a group of enzymes that are present in the cells of all internal organs, but are most active in hepatocytes. These include alanine aminotransferase (ALT, ALT) and aspartate aminotransferase (AST, AsAT).

Aspartate aminotransferase (AST, AST)

The liver, heart, muscles, kidneys and brain are the organs with the highest amount of AST. This enzyme enters the blood when any of these organs is damaged. For example, the level of AST in the blood increases with heart attacks and muscle injuries. Aspartate aminotransferase is not considered a specific indicator of liver damage. The enzyme is a marker of the destruction of the heart muscle, and its level is assessed in myocardial infarction.

Alanine aminotransferase (ALT, ALT)

Alanine aminotransferase is considered a specific indicator of hepatocyte destruction. It predominates to a greater extent in the cytoplasm of liver cells than in the kidneys, myocardium, pancreas or skeletal muscles.

It must be understood that ALT and AST levels do not always indicate abnormal liver function, although they are included in a group of tests called “liver tests”. Even if ALT and AST are greatly elevated, the liver may still function properly. For an accurate understanding of the reasons for the increase in ALT and AST, it is necessary to consult a doctor.

ALT and AST limits

While reference values ​​for AST and ALT may vary from laboratory to laboratory, the upper limit of normal is typically 40 units per liter of serum (blood fluid) for AST and 50 units per liter of serum for ALT.

Women tend to have lower levels of transaminases (ALT, AST) than men. In the elderly, AST and ALT levels are usually slightly higher than the normal range for adults.

In children, the level of ALT and AST in the blood is slightly higher than adult norms – this is not a pathology.

AST and ALT ranges may vary slightly depending on the technique and protocols used by various laboratories around the world. Usually laboratories indicate the range of reference values ​​​​of indicators on the test forms.

ALT/AST above normal

It must be understood that the increase in transaminases (AST and ALT) is not an independent disease – it is only a consequence of the disease. To reduce the level of AST and ALT in the blood, it is necessary to eliminate the cause of the increase in enzymes.

One of the most common causes of slight elevations in ALT and AST in asymptomatic individuals is chronic alcohol use. Many prescription drugs also cause an increase in ALT. [1]

Very high levels of ALT and AST (greater than 10 times normal) are usually associated with acute hepatitis. ALT and AST can also be severely elevated (sometimes more than 100 times normal) by exposure to drugs or other substances that are toxic to the liver, or by conditions that cause decreased blood flow to the liver.