What are the other Names for this Test? (Equivalent Terms)
- Normetanephrine Blood Test
- Plasma Metanephrines Test
- Total Metanephrines Blood Test
What is Plasma Free Metanephrines Test? (Background Information)
- The adrenal glands are responsible for producing catecholamines, a group of hormones that includes adrenaline. Catecholamines are essential to the body’s “fight-or-flight” response
- Catecholamines do not circulate in the blood forever. Once they are done exerting their effects, the body breaks down these hormones. The breakdown products, metanephrine and norepinephrine, are collectively referred to as metanephrines
- In the case of an adrenal gland disorder, such as a tumor, the production of catecholamines may be significantly increased. Thus, levels of metanephrines are also higher, because more catecholamines are being broken down
- The Plasma Free Metanephrines Test is a blood test that measures the levels of metanephrines in circulation. It is used as a diagnostic tool for pheochromocytoma and other adrenal gland disorders
What are the Clinical Indications for performing the Plasma Free Metanephrines Test?
The following conditions, if present at rest, are clinical indicators for performing the Plasma Free Metanephrines Test:
- Rapid heart rate
- High blood pressure
How is the Specimen Collected for Plasma Free Metanephrines Test?
Sample required: Blood
Process: Insertion of needle into a vein, after the individual lies face-up, for 20 minutes.
What is the Significance of the Plasma Free Metanephrines Test Result?
Elevated levels of metanephrines may indicate:
- Adrenal gland disorder or tumor, such as pheochromocytoma
- Excessive and chronic stress
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- Adrenal gland tumors are usually not cancerous - that is, they do not usually spread to other tissues (a process known as metastasis)
- Certain factors may interfere with the test and these include: Certain foods that contain methylxanthine, such as coffee, chocolate, tea; and many medications
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
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References and Information Sources used for the Article:
http://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=167&ContentID=metanephrines_blood (accessed 2/4/14)
Jacobs, D. S., Oxley, D. K., & DeMott, W. R. (2004). Laboratory test handbook: Concise, with disease index (3rd ed.). Hudson (Cleveland), OH: Lexi-Comp.
Lenders J, Pacak K, McClellan W (2002.) “Biochemical diagnosis of pheochromocytoma: which test is best?”. JAMA 287 (11): 1427-34