24-Hour Urinary Catecholamines
The adrenal glands are responsible for the production of the catecholamines hormones, as a response to stress. They alert the person experiencing stress by increasing the blood flow to the brain, heart and the kidneys, preparing the person for an instant fight-or-flight reaction. The catecholamines thus increase breathing, heartbeats, alertness, blood pressure and muscle strength and lower the blood flow to the skin. These hormones are broken down by the body and are eliminated through urine. Therefore, a 24-hour urinary catecholamine test is used to measure the levels of these hormones in a urine sample.
Why is the test ordered?
The test may be useful as a follow-up test to urine metanephrine or plasma free metanephrines for confirming the diagnosis of adrenal gland tumours: pheochromocytomas and paragangliomas in individuals with symptoms. It may also be recommended to monitor the progress of the treatment of the disorder.
When is the test ordered?
The test may be recommended when the metanephrines urine test and plasma free metanephrine tests are inconclusive and a doctor wants further information about a potential adrenal tumour. Furthermore, it may also be recommended when a young individual complaint of the abrupt emergence of the following signs and symptoms:
- Rapid heart rate
- Severe headache
- High blood pressure (which is non-responsive to the treatment)
How is the sample collected?
A urine sample over a period of 24 hours is collected in a sterile container.
How to prepare for the test?
Avoid tea, coffee, bananas, citrus fruits, vanilla, walnuts, fava beans, avocados, cocoa, licorice, vanilla and chocolate for 2 to 3 days before the test as they affect the test results. Drink plenty of fluids, keep yourself warm, and don’t consume tobacco during the 24-hour urine collection period. Inform the doctor about all the medicines you are taking and follow his/her instructions.