Urine Metanephrines
The Test Sample
What is being tested?
Urine metanephrine testing measures the amount of both metanephrine and normetanephrine. These metabolites are usually present in the urine in small fluctuating amounts that increase appreciably during and shortly after the body is exposed to a stressor. Pheochromocytomas and other neuroendocrine tumors, however, can produce large amounts of catecholamines, resulting in greatly increased concentrations of the hormones and their metabolites in both the blood and urine. The catecholamines that a pheochromocytoma produces can cause persistent hypertension (high blood pressure) and/or bouts or episodes of severe hypertension. Other symptoms of catecholamine release include headaches, palpitations, sweating, nausea, anxiety, and tingling in the extremities.
About 90% of pheochromocytomas are located in the adrenal glands. While a few are cancerous, most are benign – they do not spread beyond their original location - although most do continue to grow. Left untreated, the symptoms may worsen as the tumor grows and, over a period of time, the hypertension that the pheochromocytoma causes may damage body organs, such as the kidneys and heart, and raise the risk of an affected patient having a stroke or heart attack.
The metanephrine test can be used to help detect the presence of pheochromocytomas. Although, according to the National Cancer Institute, only about 800 cases a year are diagnosed in the U.S., it is important to diagnose and treat these rare 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 associated symptoms and complications.
How is the sample collected for testing?
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?






