ALP isoenzyme test
Alkaline phosphatase (ALP) is an enzyme found in many body tissues such as liver, bile ducts, bone, and intestine. There are several different structural forms of ALP called isoenzymes. The structure of the enzyme depends on where in the body it is produced. This test is most often used to test ALP made in the tissues of the liver and bones.
The ALP isoenzyme test is a lab test that measures the amounts of different types of ALP in the blood.
Alkaline phosphatase isoenzyme test
How the Test is Performed
A blood sample is needed. Most of the time blood is
How to Prepare for the Test
Many medicines can interfere with blood test results.
- Your health care provider will tell you if you need to stop taking any medicines before you have this test.
- DO NOT stop or change your medicines without talking to your provider first.
How the Test will Feel
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.
Why the Test is Performed
When the ALP test result is high, you may need to have the ALP isoenzyme test. This test will help determine what part of the body is causing higher ALP levels.
This test may be used to diagnose or monitor:
- Bone disease
Liver, gallbladder, or bile duct disease
- Pain in the abdomen
- Parathyroid gland disease
Vitamin D deficiency
It may also be done to check liver function and to see how medicines you take may affect your liver.
The normal value for total ALP is 44 to 147 international units per liter (IU/L) or 0.73 to 2.45 microkatal per liter (µkat/L). ALP isoenzyme testing may have differing normal values.
Adults have lower levels of
The isoenzyme test results can reveal whether the increase is in "bone" ALP or "liver" ALP.
Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
The example above shows the common measurement range for results for these tests. Some laboratories use different measurements or may test different specimens.
What Abnormal Results Mean
Higher-than-normal ALP levels:
- Biliary obstruction
- Bone disease
- Eating a fatty meal if you have blood type O or B
- Healing fracture
- Liver disease
- Osteoblastic bone tumors
Paget diseaseof bone
Lower-than-normal levels of ALP:
- Pernicious anemia
Proteindeficiency Wilson disease
- Zinc deficiency
Levels that are only slightly higher than normal may not be a problem unless there are other signs of a disease or medical problem.
Other conditions for which the test may be done:
- Alcoholic liver disease (hepatitis/cirrhosis)
- Alcohol use disorder
- Biliary stricture
- Giant cell (temporal, cranial) arteritis
- Multiple endocrine neoplasia (MEN) II
- Renal cell carcinoma
Fogel EL, Sherman S. Diseases of the gall bladder and bile ducts. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 146.
Korenblat KM, Berk PD. Approach to the patient with jaundice or abnormal liver tests. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier ; 2020:chap 138.
Martin P. Approach to the patient with liver disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier ; 2020:chap 137.
Weinstein RS. Osteomalacia and rickets. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 231.
Review Date: 06/20/2023
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