Alkaline phosphatase (ALP) is a protein found in all body tissues. Tissues with higher amounts of ALP include the liver, bile ducts, and bone.
A blood test can be done to measure the level of ALP.
A related test is the ALP isoenzyme test.
A blood sample is needed. Most of the time blood is drawn from a vein located on the inside of the elbow or the back of the hand.
You should not to eat or drink anything for 6 hours before the test, unless your health care provider tells you otherwise.
Many medicines can interfere with blood test results.
You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.
Reasons the test may be done include:
The normal range is 44 to 147 international units per liter (IU/L) or 0.73 to 2.45 microkatal per liter (µkat/L).
Normal values may vary slightly from laboratory to laboratory. They also can vary with age and gender. High levels of ALP are normally seen in children undergoing growth spurts and in pregnant women.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
Abnormal results may be due to the following conditions:
Higher-than-normal ALP levels
Lower-than-normal ALP levels
Other conditions for which the test may be done:
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.