An alkaline phosphatase (ALP) enzyme helps to break down proteins in the body. A healthcare professional can measure the amount of ALP in a person’s bloodstream. High ALP levels can indicate certain liver issues.

A person can have high ALP levels due to natural occurrences, such as pregnancy or bone growth. However, high ALP levels can also result from a problem with the liver.

ALP tests help a healthcare professional check a person’s liver function. This can help determine the health of the person’s liver.

This article details ALP liver enzymes, ALP tests, and what different levels of ALP enzymes can mean.

A vial of blood that doctors will test for an ALP liver enzyme.Share on Pinterest
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ALP is an enzyme that is present in many areas of the body.

Most of the body’s ALP is in the liver, bones, kidneys, and intestines. A person’s liver and bones are the main places that create ALP.

There are four types of ALP in the body. These are:

  • intestinal ALP
  • placental ALP
  • placental-like ALP
  • liver, bone, kidney, or tissue non-specific ALP

Scientists are currently unsure of ALP’s exact function. However, they believe it plays a part in multiple bodily functions, such as:

  • bone mineralization
  • vitamin B6 metabolism
  • neurogenesis, which is the formation of new neurons inside the brain
  • breaking down proteins

An ALP test is a blood test that measures the amount of ALP in a person’s bloodstream. Elevated ALP levels can indicate that a person has an issue with their liver.

A healthcare professional may recommend an ALP test on its own. However, they mostly use ALP tests as part of a liver panel test. Liver panel tests measure the amounts of different substances in a person’s blood.

Different levels of different substances can indicate certain liver conditions. Healthcare professionals can use liver panel tests to determine the cause of a person’s liver damage.

Information from 2021 indicates that various liver conditions can elevate ALP levels.

A healthcare professional may order an ALP test if a person shows signs of liver damage. However, ALP tests alone may not be enough to diagnose specific issues.

Instead, ALP tests can help determine the type or severity of a person’s condition.

Doctors may also perform regular ALP tests to monitor a person’s condition. ALP levels can indicate how a person is responding to treatment.

Learn more about abnormal ALP levels here.

Symptoms of a liver problem

Certain symptoms may indicate that a person has a problem with their liver. These symptoms include:

A person should not need to prepare before an ALP test. If a person is having an ALP test as part of a liver panel test, their healthcare professional will make them aware of any specific preparations required.

People who have type O or B blood may need to fast for 12 hours before an ALP test, as their ALP levels can increase after eating a fatty meal.

An ALP test involves taking a sample of a person’s blood using a needle. It may involve the following steps:

  1. A healthcare professional may place an elastic band around a person’s arm. This helps to increase blood flow through the veins.
  2. They may then wipe the area they are going to insert the needle with an antiseptic wipe.
  3. They then insert the needle into a person’s arm. This may cause slight stinging or discomfort.
  4. They will draw a small amount of blood through the needle and into a vial or test tube.
  5. When they have collected enough blood, the healthcare professional removes the needle from the person’s arm.
  6. They may then ask the person to hold a cotton pad on the area they took blood from and then place a plaster over it.

An ALP test should take less than 5 minutes. A person may experience slight pain or bruising in the area, but this should clear quickly.

Alternatively, at-home ALP tests are sometimes available. A person performs a home ALP test by pricking their finger and filing a vial with blood. This blood sample is then sent to a laboratory for analysis.

A person should receive their ALP test results a few days after the ALP test. If ALP levels show elevation but other liver function results are normal, it can indicate that a liver problem is not the cause.

However, if ALP levels are high and other liver function results are abnormal, it can mean that a person has an issue with their liver.

A healthcare professional will measure a person’s ALP levels using international units per liter (IU/l). Normally, ALP levels are around 44⁠–147 IU/L. This figure may vary from laboratory to laboratory.

Normal ALP levels can depend on a person’s age and if they are pregnant. ALP can naturally be higher in adolescents and pregnant people.

If a person has abnormally high levels of ALP, it can indicate liver damage. A healthcare professional may order further tests to determine the cause of a person’s liver problem.

If a person has liver damage, it can leak ALP into their bloodstream. This causes the ALP blood level to increase.

Various conditions can cause liver damage, such as:

Treatment for abnormal ALP levels can depend on the cause. Doctors may use the following treatments for different liver conditions:

  • If a person has an obstruction in their liver or bile duct, they may require a procedure to remove the obstruction.
  • A doctor may prescribe antibiotics if a person’s liver damage is due to infection.
  • Acute viral hepatitis A will usually clear up on its own without treatment. However, hepatitis B and C may require treatment.
  • Severe hepatitis or cirrhosis may require a liver transplant.
  • If a person has liver cancer, they may require chemotherapy, radiation therapy, or surgery.
  • A person cannot reverse cirrhosis. However, medications are available to treat the symptoms.
  • Giving up alcohol or drugs may help prevent further damage to the liver.

A healthcare professional can discuss with a person about the best treatment for their condition.

An ALP liver enzyme is important for various bodily processes. Doctors can measure ALP enzyme levels using an ALP test.

ALP tests take less than 5 minutes. The test involves a healthcare professional taking a small blood sample from a person’s arm.

High ALP levels could indicate an issue with the liver. However, age and circumstances also play a role in ALP enzyme levels — adolescents and pregnant people tend to have higher ALP levels.

Various conditions can cause liver damage. A person can talk with their healthcare professional about the right treatment for them.