Test Details & Preparation
An alkaline phosphatase level test (ALP test) measures the amount of alkaline phosphatase enzyme in your bloodstream. The test requires a simple blood draw and is often a routine part of other blood tests.
Abnormal levels of ALP in your blood most often indicate a problem with your liver or bones. However, they may also indicate malnutrition, kidney tumours, or a serious infection. The normal range of ALP varies from person to person and depends on your age, blood type, and sex.
An ALP test may be performed to determine how well your liver is functioning or to identify problems with your bones. Checking ALP levels in the blood is a routine part of a liver function test used to determine if your liver is diseased or damaged.
The ALP test can be helpful in identifying conditions such as hepatitis, cirrhosis, cholescystitis and blockage of bile ducts.
You may also need an ALP test if you are taking a medication that has the potential to damage your liver, such as acetaminophen (Tylenol). Measuring ALP is one way to check for that damage.
The ALP test can be helpful in the diagnosis of bone problems such as rickets, osteomalacia and Paget’s disease. ALP testing can also be helpful in investigating vitamin D deficiency, the presence of tumours, or unusual bone growth.
Having blood drawn for an ALP test is routine, and you will most likely not need to do anything to prepare ahead of time. If the results of the test are inconclusive, your doctor may order a follow-up test. In this case, you will probably be asked to fast for 10 hours before the test.
Higher-than-normal levels of ALP in your blood may indicate a problem with your liver. This could include hepatitis (infection), cirrhosis (scarring), liver cancer, gallstones, or a blockage in your bile ducts.
High levels may also indicate an issue related to the bones such as rickets, Paget’s disease, bone cancer, or an overactive parathyroid gland. In rare cases, high ALP levels can indicate heart failure, kidney cancer, mononucleosis, or a blood infection.
Having lower-than-normal ALP levels in your blood is rare, but can indicate malnutrition, which could be caused by celiac disease or a deficiency in vitamins and minerals.