I. What is Alkaline Phosphatase (ALP) Testing?

Chronic liver disease causes more than 44,000 deaths per year in the United States. ALP testing can help diagnose liver disease before it becomes fatal.

Why should you get tested?

You should get the ALP test if you have symptoms of a liver or bone disorder, such as abdominal pain or bone pain.

Who should get tested?

Anyone with persistent symptoms of liver disease or a bone disorder should have the ALP test. Your doctor may also order the test as part of a routine physical to check your liver function.

When to get tested

You should get tested as soon as your doctor recommends it.

II. How to Prepare for Alkaline Phosphatase (ALP) Testing

If you’re having the ALP test by itself, you don’t need to do any special preparation. The test is often performed as part of a comprehensive metabolic panel, which also measures your blood sugar, electrolyte levels, and kidney function. If you’re getting the CMP, your doctor may ask you to fast for at least eight hours before the test to ensure these measurements are as accurate as possible.

III. How an Alkaline Phosphatase (ALP) Test Works

The ALP test measures the amount of alkaline phosphatase in your bloodstream. When your doctor orders the ALP test, you can expect to have blood drawn by a medical technician. After asking some questions about your medical history and why you’re having the test, the technician will examine your arm to identify the best site for drawing blood. If your veins are difficult to see, the technician may press on your arm or ask you to make a fist. After cleansing your skin, the technician will insert a needle into the vein and use a specimen tube to collect a blood sample. The sample is processed by a clinical laboratory, and the results will be sent to the ordering physician.

IV. Understanding Alkaline Phosphatase (ALP) Testing Results

You should receive your ALP results within a few days of having your blood drawn. The turnaround time depends on how busy the lab is and how long it takes your doctor to review the results and contact you. Depending on your doctor’s communication preferences, you may receive the results via telephone, or you may have to download the result from an online portal. A normal alkaline phosphatase (ALP) level usually ranges from 20 to 140 international units per liter. An abnormally high ALP level doesn’t necessarily mean anything is wrong with your liver or bones, so it’s best to discuss the results with your doctor to determine what they mean for your specific circumstances.


What is a normal ALP level?

A normal ALP level usually ranges from 20 to 140 international units per liter; however, some labs have different reference ranges. The normal range for a particular lab will be printed on the report with the results.

If my ALP is high, do I definitely have something wrong with my liver?

Not necessarily. Because ALP is found in other parts of the body, such as the bones and kidneys, it’s possible to have an elevated ALP level and still have normal liver function.

What other tests will I need if my ALP level is high?

Additional tests may be needed if the ALP test result is abnormal. For people with any of the risk factors for liver problems, the ordering physician will review the results of the ALP test as well as other indicators of liver function. These indicators include total protein, albumin, and bilirubin. If these tests are also abnormal, a health care provider is likely to order an ultrasound or CT scan to determine if the liver has any structural or functional abnormalities.

If the other liver function tests are normal, it’s possible the excess ALP is coming from a source other than the liver. A health care provider may order a basic metabolic panel to assess the individual’s kidney function or isoenzyme tests to determine if the high ALP level stems from a problem with the bones. Isoenzyme testing can distinguish ALP released by the bones from ALP released by the liver based on the structure of each substance.

What are the risks of having the ALP test?

The ALP test has relatively few risks. Any time an individual has blood drawn, there is a risk that bacteria from the skin will get into the bloodstream and cause an infection; however, the risk is low. Some people feel ill while they are having blood drawn, but this usually goes away once the needle is removed from the vein and a bandage has been placed over the insertion site.

Are low ALP levels a concern?

High ALP levels are more concerning than low ALP levels, but a low ALP level can be a sign of certain medical problems. These problems include protein deficiency, malnutrition, and Wilson disease, a genetic disorder that causes copper to accumulate in the body’s tissues.

VI. Learn From Our Alkaline Phosphatase (ALP) Testing Sources

Want to know more about alkaline phosphatase (ALP) testing? Consult the sources used to prepare this article.