To help confirm or rule out a rare tumor of the adrenal gland called a pheochromocytoma or a rare tumor outside of the adrenal gland called a paraganglioma; these tumors (PPGL) produce excess catecholamines, which are broken down to metanephrines.
To help confirm or rule out a rare tumor of the adrenal gland called a pheochromocytoma or a rare tumor outside of the adrenal gland called a paraganglioma; these tumors (PPGL) produce excess catecholamines, which are broken down to metanephrines.
After or along with plasma free metanephrines and/or urine metanephrines tests and when your healthcare practitioner needs additional information about a possible tumor that produces catecholamines
A 24-hour urine sample; sometimes a blood sample drawn from a vein
These tests are affected by certain drugs, foods, and stresses. Tell your health care practitioner about any medications you are taking and follow any preparation instructions you are given before sample collection. Although you may be seated for collection of the blood sample, it is recommended that you be lying down. Your health care practitioner or the collection site will instruct you as to their specific requirements.
Catecholamines are a group of similar substances released into the blood in response to physical or emotional stress. The primary catecholamines are dopamine, epinephrine (adrenaline), and norepinephrine. Catecholamine testing measures the amounts of these hormones in the urine and/or blood. Urine testing is recommended over blood testing. Just the stress of having blood drawn can increase catecholamine blood levels, so results from blood tests are not as reliable as results from urine tests.
Catecholamines are produced in the adrenal medulla, the interior portion of the adrenal glands, and released into the blood. The adrenal glands are small, triangular organs located on top of each kidney. Catecholamines are also produced by cells of the sympathetic nervous system. They are released into the blood in response to physical and emotional stress. They help transmit nerve impulses in the brain, increase glucose and fatty acid release for energy, dilate bronchioles, and dilate the pupils. Norepinephrine also constricts blood vessels, causing increased blood pressure, and epinephrine increases heart rate and metabolism.
After completing their actions, catecholamines are metabolized to inactive compounds. Dopamine becomes homovanillic acid (HVA), norepinephrine breaks down into normetanephrine and vanillylmandelic acid (VMA), and epinephrine becomes metanephrine and VMA. Both the hormones and their metabolites are eliminated from the body in the urine.
Normally, catecholamines and their metabolites are present in the body in small, fluctuating amounts that only increase appreciably during and shortly after a stressful situation. However, rare tumors called pheochromocytomas and paragangliomas (collectively called PPGL) can produce large amounts of the hormones, resulting in increased concentrations in both the blood and urine. This can cause persistent or sudden bursts of hypertension, which may lead to severe headaches. Other symptoms include heart palpitations, sweating, nausea, anxiety, and tingling in the hands and feet.
Pheochromocytomas and paragangliomas are rare. While a few are cancerous, most are benign and do not spread beyond their original location. Left untreated, however, these tumors may continue to grow and symptoms may worsen. Over time, the hypertension caused by the excess hormones may lead to kidney damage, heart disease, and raise the risk for stroke or heart attack.
It is important to diagnose and treat these tumors because they cause a potentially curable form of hypertension. In most cases, the tumors can be surgically removed and/or treated to significantly reduce the amount of catecholamines being produced and to reduce or eliminate their associated symptoms and complications.
How is the sample collected for testing?
For the urine test, a 24-hour urine collection is needed. All urine is saved for a 24-hour period. It is important that the sample be refrigerated during this time. A preservative is required and is usually provided with the collection container.
Blood for catecholamine testing is collected by inserting a needle into a vein. Although you may be seated for the collection, it is recommended that you be lying down. The health care practitioner or the collection site will instruct you as to their specific requirements.
Is any test preparation needed to ensure the quality of the sample?
Catecholamine levels are affected by certain drugs, foods, and stresses. Preparation for the test is important to ensure that an appropriate sample is collected and for correct interpretation of results. Follow any instructions given by the health care practitioner or the collection site or laboratory.
This form enables patients to ask specific questions about lab tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. Please allow 2-3 business days for an email response from one of the volunteers on the Consumer Information Response Team.
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