AMP; Dermatan sulfate - urine; Urine heparan sulfate; Acid mucopolysaccharides; Heparan sulfate - urine
This is a test that measures the amount of mucopolysaccharides excreted in the urine over a 24-hour period.
How the test is performed
A 24-hour urine sample is needed.
The health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test.
- On day 1, urinate into the toilet upon arising in the morning.
- Collect all subsequent urine (in a special container) for the next 24-hours.
- On day 2, urinate into the container in the morning upon arising.
- Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed. Deliver it to the laboratory or your health care provider as soon as possible upon completion.
How to prepare for the test
No special preparation is needed. Drink a normal volume of fluids, and consume a normal diet.
How the test will feel
The test involves only normal urination, and there is no discomfort.
Why the test is performed
This test is performed to detect a rare disorder of excess acid mucopolysaccharides accumulation (especially dermatan sulfate and heparan sulfate) in the tissues. The severe form of this disorder can lead to Hurler’s syndrome. Typically this test is only ordered for infants where there is a family history of mucopolysaccharidosis.
Normal acid mucopolysaccharide values vary with age, and the normal range of values varies among laboratories. The laboratory performing the test should be consulted for interpretation of the test result.
What abnormal results mean
Abnormally high levels of acid mucopolysaccharides reliably indicate mucopolysaccharidosis, and further detailed studies can identify which enzyme is defective.
What the risks are
There are no risks (except for the chance of inaccurate results if all of the urine is not collected during the 24-hour period).
If the test was performed on an infant, remove all remaining collection-device adhesive from the skin with warm soap and water.
by Dave R. Roger, M.D.