Alkaline phosphatase (alp) test

An alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in your blood. ALP is made mostly in the liver and in bone, with some made in the intestines and kidneys.

The ALP test is done to:

• Check for liver damage when you're taking medicines that can damage the liver.
• Help look for liver disease. Liver disease may cause symptoms. These may include pain in the upper belly, nausea, vomiting, and sometimes jaundice.
• Check for bone problems (sometimes found on X-rays). Some examples are rickets, osteomalacia, bone tumors, and Paget's disease. The test can also check for too much parathyroid hormone. This is the hormone that controls bone growth.
• Check to see how well treatment for Paget's disease or a vitamin D deficiency is working.

A health professional uses a needle to take a blood sample, usually from the arm.

• If you are having a follow-up ALP test, you may be asked to not eat or drink for 10 hours before the test. The ALP level generally goes up after eating, especially after you eat fatty foods.
• Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies you take. Some may increase the risk of problems during your test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

High values

• Very high levels of ALP can be caused by liver problems, such as hepatitis, blockage of the bile ducts (obstructive jaundice), gallstones, cirrhosis, liver cancer, or cancer that has spread (metastasized) to the liver from another part of the body.
• High ALP levels can be caused by bone diseases, such as Paget's disease, osteomalacia, rickets, bone tumors, or tumors that have spread from another part of the body to the bone, or by overactive parathyroid glands (hyperparathyroidism). Normal healing of a bone fracture can also raise ALP levels.
• Heart failure, heart attack, mononucleosis, or kidney cancer can raise ALP levels. A serious infection that has spread through the body (sepsis) can also raise ALP levels.
• ALP levels are higher during the third trimester of pregnancy because the placenta makes ALP.

Low values

Low levels of ALP can be caused by:

• Conditions that lead to malnutrition, such as celiac disease.
• A lack of nutrients in the diet.
• An inherited bone disease called hypophosphatasia.