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Alternative names Return to top
Dopamine-urine test; Epinephrine-urine test; Adrenalin-urine test; Vanillylmandelic acid (VMA); Urine metanephrine; Normetanephrine; Norepinephrine-urine test; Urine catecholamines; VMA; HVA; Metanephrine; Homovanillic acid (HVA)Definition Return to top
This is a urine test that measures the level of catecholamines or catecholamine metabolites (break-down products).How the test is performed Return to top
Catecholamines can be measured in the blood or urine.
A 24-hour urine sample is needed. Your health care provider will instruct you, if necessary, to discontinue drugs or activities that may interfere with the test (see "How to prepare for the test").
For an infant:
Thoroughly wash the area around the urethra (the hole where urine flows out). Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Place a diaper over the infant (bag and all).
The infant should be checked frequently and the bag changed after the infant has urinated into the bag. For active infants, this procedure may take a couple of attempts since lively infants can displace the bag. The urine is drained into the container for transport to the laboratory.
Deliver it to the laboratory or your health care provider as soon as possible upon completion.
How to prepare for the test Return to top
Certain foods can increase urinary catecholamines, including coffee, tea, bananas, chocolate, cocoa, citrus fruits, and vanilla. Avoid these for several days prior to the test.How the test will feel Return to top
The test involves only normal urination, and there is no discomfort.Why the test is performed Return to top
The test is used primarily to screen for, diagnose, and monitor treatment of pheochromocytoma or neuroblastoma.
Catecholamines are chemically similar small molecules derived from the amino acid tyrosine. The major catecholamines are dopamine, norepinephrine, and epinephrine (old name: adrenalin).
Dopamine is a neurotransmitter (a chemical used to transmit impulses between nerve cells) found mainly in the brain. Norepinephrine is the primary neurotransmitter in the sympathetic nervous system (controls the "fight or flight" reaction) and is also found in the brain. Epinephrine is not only a brain neurotransmitter, but also a major hormone in the body.
Epinephrine is secreted from the adrenal medulla in response to low blood glucose, exercise, and various forms of acute stress (in the latter case, the brain stimulates release of the hormone). Epinephrine causes a breakdown of glycogen to glucose in liver and muscle, the release of fatty acids from adipose tissue, vasodilation of small arteries within muscle tissue, and increases the rate and strength of the heartbeat.
All of the catecholamines are metabolized by their target tissues or by the liver to become inactive substances that appear in the urine:
Normal Values Return to top
Note: mg/hour = milligrams per hour; mcg/hour = micrograms per hour.
What abnormal results mean Return to top
Elevated levels of urinary catecholamines may indicate:What the risks are Return to top
There are no risks.Special considerations Return to top
The accuracy of the test can be affected by several foods and drugs as well as physical activity and stress (See "How to prepare for the test"). Update Date: 8/18/2003 Updated by: David Webner, M.D., Sports Medicine Fellow, Crozer-Keystone Family Practice Program, Springfield, PA. Review provided by VeriMed Healthcare Network.
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Page last updated: 28 October 2004 |