What is an ALT blood test?

What is an ALT Blood Test?

January 2, 2024

Leon Robinson

Monitoring the health of your liver is vital because of the variety of bodily functions it affects. The liver removes excess sugar from the blood, helps the body digest food, and stores vitamins and minerals for later use. The liver also makes substances that help clot the blood and filter the blood to remove waste and toxins.

Alanine Aminotransferase (ALT) is an enzyme found in your liver. ALT is also known as serum glutamic-pyruvic transaminase or SGPT. ALT’s primary function is to help the liver break down proteins to make them easier for the body to absorb. ALT/SGBT is also the most useful enzyme for identifying the presence of liver damage.

What is an Alanine Aminotransferase ALT/SGBT Blood Test?

The alanine aminotransferase (ALT) blood test is often used in routine screenings to check the health of the liver. Normally, the body uses the ALT enzyme to break down food into energy. When liver cells are damaged, they release higher levels of ALT that can leak into the blood. Elevated levels of ALT in your blood can be a warning sign of liver disease.

What are the Symptoms of High or Low ALT?

The ALT test is typically ordered for diagnostic purposes when someone is experiencing signs and symptoms that are commonly associated with liver damage. These can include:

  • Nausea or vomiting.
  • Belly (abdominal) pain.
  • Itchy skin.
  • Jaundice (a yellowing of your skin and the whites of your eyes).
  • Tiredness (fatigue).
  • Appetite loss.

Lower than normal ALT levels are not usually a cause for concern unless coupled with other abnormal test results or unusual symptoms.  Factors such as smoking, vitamin B6 deficiency, or hormone replacement therapy can contribute to lowered ALT.

What are the Causes of High ALT/SGBT?

Only a small percentage of people with high ALT levels will turn out to have a liver condition. ALT numbers can be higher in men than in women and younger children. Levels also tend to be higher in younger people as opposed to older people. People with Mexican American heritage are also known to have higher ALT levels. An increased ALT level may indicate the following conditions:

  • Alcohol-induced liver injury.
  • Fatty liver disease (too much fat in your liver).
  • Hepatitis (liver inflammation).
  • Cirrhosis (scarring of the liver).
  • Taking medications that are toxic to your liver.
  • Liver tumor or liver cancer.
  • Liver ischemia (not enough blood flow to your liver, which leads to death of liver tissue).
  • Hemochromatosis (having too much iron in your body).
  • Mononucleosis ("mono").
  • Certain genetic conditions can affect your liver.

Elevated ALT levels are not always a sign of illness.  Other factors can cause an increase in ALT levels. High ALT could be caused by taking certain medicines, exercising intensely, or for women, during a menstrual period. Follow-up testing will often be necessary to diagnose liver problems.

Aspartate transaminase (AST) is another enzyme commonly measured alongside ALT. Comparing ALT with AST levels provides more information about the liver's health. Both are considered liver enzymes, but ALT is more directly tied to liver health. Healthcare providers will use both measurements to assess the health of the liver. The AST-to-ASL ratio can help figure out how severe the liver damage is and what might have caused it. If levels of both enzymes are high, it is diagnosed as elevated liver enzymes. With elevated liver enzymes, the cause for concern is only if the levels remain high. In about a third of the cases, they return to normal after 2-4 weeks. If ALT levels don't return to normal, you may be advised to get more tests and advised to see a liver specialist.

What are other risk factors for liver disease?

A healthcare provider may also recommend an ALT test if someone has one or more risk factors for liver disease, even if they aren’t experiencing any symptoms.  Diagnosing liver disease early can improve the chances of successful treatment and avoiding long-term illnesses.  Risk factors for liver disease include: 

  • Heavy alcohol use.
  • Family history of liver disease.
  • Taking medicines/painkillers that cause liver damage.
  • Obesity.
  • Diabetes.
  • The sharing of needles for drug use.
  • Exposure to viral Hepatitis.

Where can I get an ALT Blood Test Near Me?

Request A Test offers a variety of online lab tests to monitor healthy liver function. Our goal is to give everyone the ability to take charge of their health by offering affordable lab testing that anyone can order without having to visit a doctor or go through an insurance provider.  You can order individual tests for ALT and AST or combine them with other liver function measurements in the Hepatic Function Test.  Our menu includes a number of panels that combine liver testing with other general wellness tests for a more comprehensive health screening.  Take a look at packages such as the Basic Wellness PanelMen's Health Panel, and Women's Health Panel to find a package that works best for you.  When you're ready to order, choose from over 4,000 testing locations across the US.  Visit us online or call our team at 888-732-2348 to start an order today.


Alanine Aminotransferase Test (ALT) or (SGPT): normal range & results (webmd.com)

Alanine Transaminase (ALT) Blood Test: What It Is, Procedure & Results (clevelandclinic.org)

ALT Blood Test: MedlinePlus Medical Test

Low ALT: Causes & Health Effects - SelfDecode Labs


DISCLAIMER: The medical information in this post is for informative purposes only.

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