• Monday - Friday
    9am – 6pm
  • Saturday - Sunday
    10am – 2pm

ALT blood test

Alanine transaminase (ALT) is an enzyme present mostly in the liver. The ALT test measures the amount of ALT in the blood. Damaged liver cells release ALT into the bloodstream. A high ALT level in the blood may mean a liver disease or injury.

Some types of liver disease result in high ALT levels before symptoms become noticeable. This means an ALT blood test may help diagnose some liver diseases early.

Other names for the ALT blood test are alanine aminotransferase (ALT), GPT and Serum Glutamic-Pyruvic Transaminase (SGPT).

What is the test for?

The ALT test helps assess the liver health. If the cells in the liver get damaged, they leak ALT into the blood, so the test can diagnose liver problems.

ALT testing is usually done with other tests for liver compounds and enzymes in the blood. These tests are useful for screening, diagnosing and monitoring liver-related issues.

Why do I need an ALT blood test?

Your healthcare provider may request an ALT blood test during your routine check-up. ALT testing is done alongside a group of tests known as liver function tests that assess the liver’s health. The healthcare provider may also order these tests if you experience symptoms of liver damage such as:

  • Weakness
  • Lack of appetite
  • Fatigue
  • Swelling or pain in the abdomen (belly)
  • Vomiting and nausea
  • Jaundice – a condition that makes the eyes and skin yellow
  • Dark-coloured urine and light-coloured stool (poop)
  • Swelling in the legs or ankles
  • Frequent itching

The provider may order an ALT blood test for people with a high risk of liver damage due to:

  • Diabetes
  • Obesity
  • Hepatitis or exposure to the hepatitis virus
  • Alcohol abuse disorder (AUD)
  • A family history of liver disease
  • Taking certain medications that can cause liver damage

Will I fast before an ALT blood test?

If you need the ALT test alongside a comprehensive metabolic panel (CMP), fasting for 10 – 12 hours before the CMP blood test is necessary. Fasting means you should not eat or drink anything besides water.

While it isn’t common, fasting isn’t necessary if you only undergo the ALT blood test. Your healthcare provider will provide instructions when they order the test. Ensure you follow the instructions.

What will happen during my ALT blood test?

You will likely experience the following during your ALT blood test or the blood sample collection.

  • You will sit in a chair while the healthcare provider will check your arms for a vein to draw the blood. The vein is usually on the other side of your elbow or the inner part of your arm.
  • When the provider locates a vein, they will clean and disinfect the area
  • The provider will insert a small needle into your vein to draw your blood sample. You may feel a small pinch
  • After inserting the needle, the provider will collect a small amount of blood into a test tube
  • Once they have enough blood for the ALT test, they will remove the needle and hold a cotton gauze or ball on the site to stop the bleeding.

This procedure takes less than five minutes.

When will my ALT blood test result be available?

The results are usually available in 1 – 2 business days but may take longer.

What does the ALT blood test result mean?

ALT blood tests and other blood test results usually provide the following information.

  • The blood test’s name and what was measured in your blood
  • The measurement or number of your blood test result
  • The normal range of the test
  • Information indicating the result is abnormal, normal, low or high

What is the normal range for ALT in the blood?

The normal ALT (alanine transaminase) range varies from lab to lab. However, a common reference range for this test is 7 – 56U/L (units per litre). ALT levels are usually higher in males than in females.

Checking your test report to see the lab’s specific reference range is important as the ranges vary, depending on the lab.

What does a high ALT mean?

High levels of ALT in the blood may result from injury or damage to the liver cells. Elevated ALT level may indicate the following conditions.

  • Hepatitis (liver inflammation)
  • Fatty liver disease (excess fat in the liver)
  • Alcohol-induced liver injury
  • Liver tumour or liver cancer
  • Mononucleosis (mono)
  • Liver ischemia (insufficient blood flow to the liver, which causes death of liver tissue)
  • Taking medications that are harmful to the liver
  • Haemochromatosis (excess iron in the body)
  • Cirrhosis (scarring of the liver)
  • Certain genetic conditions

Elevated ALT levels may also indicate injury in other cells because ALT is not only found in the liver but is uncommon.

However, a high level of ALT doesn’t always indicate a medical condition. People with increased ALT levels with severe liver conditions are below 5%.

Several factors can elevate ALT levels. Your healthcare provider will consider these factors, including results from other blood tests and your medical history, during your result analysis.

What does a low ALT level mean?

A lower-than-normal ALT level isn’t common and isn’t usually a cause for concern. However, it may indicate chronic kidney disease or vitamin B6 deficiency.

If your ALT result is less than normal, your healthcare provider will have you retake the test or further testing to ensure nothing is causing your low ALT level.

Is a low or high ALT level a course for concern?

A low or high ALT level doesn’t necessarily indicate a medical condition that needs treatment. Other factors that may affect your ALT levels include:

  • Exercise

    Extreme or intense exercise can temporarily increase the level of ALT in the blood.

  • Medications

    Many supplements and medications, including over-the-counter pain medications like acetaminophen, can affect ALT levels.

  • Sex

    Researchers believe hormonal differences can contribute to the variation in ALT levels in different sexes.

  • Menstruation

    ALT levels can reduce or increase during the menstrual cycle

  • Age

    ALT levels usually reduce with older age.

  • Heritage

    Research has shown that people of Mexican-American descent are more likely to have increased ALT levels.

  • Body mass index

    Several studies have established a link between body mass index (BMI) and ALT levels, which affects people with obesity.

In addition to these factors, during ALT result analysis, the healthcare provider will consider different aspects of your health and situation, such as:

  • The results of other tests done with ALT
  • Your medical history
  • How low or high the ALT results are
  • If you experience symptoms
  • Previous ALT results

Do I need a follow-up test if the ALT results aren’t normal?

Healthcare providers usually recommend follow-up tests if the ALT level is abnormal. These tests include:

  • A biopsy
  • Repeat the ALT blood test
  • Imaging tests
  • Other blood tests

Additional testing may be immediate for significantly elevated ALT levels or if you experience symptoms of a liver condition.

Every case and person is unique, so the follow-up testing plan varies. You and your doctor will determine the most suitable plan.

How much does an ALT blood test cost?

The cost of an ALT blood test varies, depending on where you conduct the test, whether you have insurance and whether you need other tests alongside ALT.

The total cost of the test may cover different components, including:

  • Charges for the blood draw by the technician
  • Charges for the office visit when you get the test prescription
  • Charges for the laboratory that measures the ALT and other blood compounds
  • Charges for an office visit to review the results

Your health insurance company will pay these charges if your doctor prescribes this test. However, some out-of-pocket costs may apply, like a copay or deductible. Contact your healthcare insurance provider for details on the specific cost of an ALT test.

When should I contact my doctor?

If you experience symptoms of liver damage, such as belly pain or jaundice, contact your doctor. Contact your doctor if you have a liver condition diagnosis and experience concerning or new symptoms. You should also contact your doctor if you have questions concerning your alanine (transaminase) ALT results.

You can call Blood London on 020 7183 0244 for more information on the ALT blood test or to book an appointment with our doctor for testing.

How Blood London Works

Order your test

Order your test

Select the test that you would like to undergo

Provide your sample

Provide your sample

Go to the Harley Street clinic for your blood draw and pay for your test in person

View your results

View your results

As soon as the results are ready, the will be sent to you by your chosen method

World class partner lab (TDL)

World class partner lab (TDL)

Advice from expert UK doctors

Advice from expert UK doctors

Repeat your tests and track your improvements!

Repeat your tests and track your improvements!

Comprehensive Blood Testing