An alkaline phosphatase (ALP) test measures the amount
enzyme ALP in the blood. ALP is made mostly in the
liver and in bone with some made in the
kidneys. It also is made by the
placenta of a pregnant woman.
makes more ALP than the other organs or the bones. Some conditions cause large
amounts of ALP in the blood. These conditions include rapid bone growth (during
puberty), bone disease (such as
Paget's disease or cancer that has spread to the bones), a disease that affects how much
calcium is in the blood (hyperparathyroidism), vitamin D deficiency, or damaged liver cells.
If the ALP level is high, more tests may be done to find the
cause. The amounts of different types of ALP in the blood may be measured and used to determine whether a high level is from the liver or bones. This is called an alkaline phosphatase isoenzymes test.
A test for alkaline phosphatase (ALP) is
An alkaline phosphatase test is often
done at the same time as a routine blood test. You do not need to do anything
before having a routine blood test.
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 eating fatty
Many medicines may change the results of this test. Be sure
to tell your doctor about all the
nonprescription and prescription medicines you
Talk to your doctor about any concerns you have regarding the
need for the test, its risks, how it will be done, or what the results will
mean. To help you understand the importance of this test, fill out the
medical test information form (What is a PDF document?).
The health professional drawing your
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
There is very little chance of a problem from
having blood sample taken from a vein.
An alkaline phosphatase (ALP) test
measures the amount of the
enzyme ALP in the blood.
The normal values listed here-called a reference range-are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
units per liter (U/L) or 0.43-1.70
Less than 350 U/L or less than 5.95
Low levels of ALP can be caused by:
Reasons you may not be able to
have the test or why the results may not be helpful include:
Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders. Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins. Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
ByHealthwise Staff Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine Kathleen Romito, MD - Family Medicine Specialist Medical Reviewer Alan C. Dalkin, MD - Endocrinology
Current as ofMay 3, 2017
Current as of:
May 3, 2017
E. Gregory Thompson, MD - Internal Medicine & Kathleen Romito, MD - Family Medicine & Alan C. Dalkin, MD - Endocrinology
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