Definition:
Alkaline phosphatase (ALP) is a substance found in all body tissues. There are many different forms of ALP. Each type has a different chemical structure, called an isoenzyme. Its structure depends on where in the body it is produced. For example, liver and bone ALP isoenzymes have different structures. The ALP isoenzyme test is a laboratory test that measures the amounts of different types of ALP in the blood. See also: Alkaline phosphatase test
Alternative Names:
Alkaline phosphatase isoenzyme test
How the test is performed:
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood. Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding. In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
How to prepare for the test:
You should not to eat or drink anything for 10 to 12 hours before the test, unless otherwise instructed by your doctor. Many drugs affect the level of alkaline phosphatase in the blood. Your health care provider may tell you to stop taking certain drugs before the test. Never stop taking any medicine without first talking to your doctor. - Allopurinol
- Antibiotics
- Anti-inflammatory medicines
- Birth control pills
- Certain arthritis drugs
- Certain diabetes medicines
- Chlorpromazine
- Cortisone
- Male hormones
- Methyldopa
- Narcotic pain medicines
- Propranolol
- Tranquilizers
- Tricyclic antidepressants
How the test will feel:
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed:
This test may be used to diagnose: It may also be done to check liver function and to see how medicines you take may affect your liver.
References:
Berk PD, Korenblat KM. Approach to the patient with jaundice or abnormal liver test results. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 150. Drezner MK. Osteomalacia and rickets. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 265.
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