November 29, 2023
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Blood Test Health Medical

The Guide of An ALT Blood Test (2023)

What is an ALT Blood Test

An ALT blood test helps to measure the ALT enzyme in the blood. ALT (Alanine transaminase) is an enzyme usually present in your liver. Enzymes are proteins that speed up the particular chemical reaction in your body. High ALT levels may appear in your blood when you have liver damage or disease. An ALT test will help examine and diagnose the conditions of your liver. In this article, you will read the complete information about the ALT enzyme with their normal ranges.

Alanine Transaminase (ALT)

ALT (Alanine transaminase) is also called Alanine Aminotransferase. This enzyme is often found in your liver, but some of it also contains in other body parts. The purpose of enzymes (protein) in the body cell is to help with specific reactions in your body, such as the digestion process, respiration, and others. Many enzymes are present in your body and each has different functions.

What is an ALT Blood Test? 

An alanine transaminase (ALT) blood test can indicate the ALT levels in your blood. Your body utilizes ALT to convert food into energy. Generally, you have low ALT levels in your blood. If you have a liver problem, an ALT enzyme will enter your blood, which may lead to an increase. A doctor can ask you for this test to check for liver injury, damage, or disease.

There are other possible factors as well that increase the ALT levels in the blood. It is the reason a healthcare provider may also use other tests to examine your liver conditions. This test may often be performed with a blood tests panel, such as a liver enzyme panel: Liver function test (LFT), or Hepatic function panel (HFP), or a comprehensive metabolic panel (CMP). These tests can give your provider more comprehensive information about more than one health condition of your body through a single blood sample.

What are the other names for an ALT blood test?

These are the common names for an ALT test, which are listed below:

  • Alanine aminotransferase
  • Alanine transaminase (ALT)
  • SGPT
  • Serum glutamic-pyruvic transaminase
  • GPT

When does a healthcare provider recommend an ALT test? 

A doctor may order this test to screen and detect the current health conditions of your liver. The increase in ALT levels in your blood is the first indication of liver problems. If you see the following signs and symptoms of liver disease, you may need to conduct this test

  • Nausea and vomiting
  • Swelling or pain in your stomach
  • The color of eyes or skin changes into yellow (jaundice)
  • Tiredness
  • Urine color turns to dark
  • Passing light-colored stools
  • Irritating or itchy skin
  • Loss of appetite


A liver blood panel test may also recommend that contains an ALT test if you have the risk factors of developing the liver disease, such as:

  • Excessive alcohol use
  • Medical or family history of liver problem
  • Being overweight
  • Diabetes or sugar problems
  • Have a hepatitis infection
  • If you are using specific medicines that affect your liver.

The other possible cause of conducting this test is to ensure the treatment is effective if you have had a liver problem. A provider often uses this test to see the extent of the liver diseases like liver damage or hepatitis infection.

What happens during an ALT Blood Test? 

You may need to visit the laboratory for a blood sample after requesting an online order for this test. A healthcare professional will guide you through the procedure of this test.


Here are the steps for collecting a blood sample for this test:

  • A provider will clean the skin area from one of your arms.
  • A small needle attached to the test tube will be injected into your vein to collect the blood.
  • A needle will be removed when your provider collects the required blood amount.
  • A bandage will apply to the vein area where the needle was inserted.
  • Your blood sample will be at the laboratory for examination.
  • This test often completes within five to ten minutes.

Things I Need To Prepare Before The Test 

You do not need specific preparation for this test. A healthcare provider may recommend fasting (avoiding eating or drinking) for a few hours if you require additional testing. Some medications may affect your ALT test result. So, inform your provider about the medicines or supplements you use.

Risk Factors Linked With An ALT Test 

An ALT blood test does not have high risks. The possible low risks before or after the test may include

  • Deposition of blood inside your skin, which is known as a hematoma.
  • Bruising
  • Infection
  • Pain or discomfort during needle injection
  • Lightheadedness
  • Dizziness

Normal Range of ALT Blood test

The ALT level is expressed in units per liter (U/L) or international units per liter (IU/L). The normal ALT test values lie between 7 to 56 units per liter (U/L).

The recommended range for an ALT may vary depending on these factors including sex, age, medical history, and others. You can schedule an online consultation with a provider to understand your test result.

What does a high ALT blood test result indicate? 

High amounts of ALT in the blood may develop because of the possibility of liver damage or liver cell injury.



  • Hepatitis (Inflammation of your liver)
  • Alcohol use disorder
  • The high-fat deposition in your liver
  • Cirrhosis (A last stage of liver disease that results in the replacement of healthy liver tissue with scar tissue)
  • Heart problems such as heart stroke or failure
  • Kidney damage
  • Liver cancer
  • Diabetes
  • Red blood cells disorder
  • Deposition of the high iron amount in the blood (Hemochromatosis)

A high ALT level does not always indicate a medical problem. The test result may also affect from other factors, such as specific medication.

Low ALT often shows your liver does not have a problem. The lower ALT levels than the recommended may show chronic kidney disease or deficiency of vitamin B12. A healthcare provider will ask to repeat the test to see the conditions that may lead to lower ALT than normal.


If the ALT blood test results are high, which is a sign of liver failure or disease, a doctor may also recommend other tests to find the hidden cause of your liver problem. You may take an e-consultation from an online provider to discuss your ALT levels.

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