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Urinalysis
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Pending specialist review and validation.
This test measures the amount of metanephrines in your urine collected over a full day. Metanephrines are breakdown products of the stress hormones adrenaline and noradrenaline. They are produced steadily as your body metabolizes these hormones, so measuring them over time provides a reliable picture of overall production.
For the test, you collect all urine for a continuous 24 hours in a special container, often with a preservative. The laboratory typically measures metanephrine and normetanephrine separately and may also report a total. Because results reflect an entire day, the test helps smooth out short-lived hormone surges that might be missed with a single sample.
Doctors use this test to help evaluate symptoms that could be caused by rare hormone-producing tumors called pheochromocytomas or paragangliomas. These tumors can trigger episodes of headaches, sweating, palpitations, and high blood pressure. The test may also be ordered if an adrenal mass is found on imaging, if you have certain inherited conditions linked to these tumors, or to monitor after treatment.
Catching excess hormone production early can prevent complications such as sudden spikes in blood pressure, heart rhythm problems, or damage to blood vessels. Because it is noninvasive and reflects hormone metabolism over an entire day, the test is a useful first step when your care team is looking for causes of unexplained spells or difficult-to-control hypertension.
Your doctor will interpret the results alongside your symptoms, medications, and how the sample was collected. Higher-than-expected amounts can suggest a tumor that makes adrenaline-like hormones, but other factors such as stress, illness, certain medications, caffeine, and incomplete collection can also raise levels. Kidney problems may affect results as well.
If results are only slightly elevated, your doctor may review your medications and diet, confirm that the collection was complete, and consider repeating the test or ordering a plasma metanephrines test. Markedly abnormal results are usually followed by confirmatory testing and, if appropriate, imaging to look for a source. Normal results make these tumors less likely, but your care team will consider the whole clinical picture before deciding on next steps.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Missing any urine during the 24 hour period, starting late, or ending early can make results unreliable. Carefully follow start and stop times and include the final void at the end.
Many labs require an acid-preserved container and cold storage during collection. Using the wrong container or leaving the jug at room temperature can degrade analytes and skew results.
Some antidepressants, decongestants, stimulants, levodopa, and monoamine oxidase inhibitors, as well as nicotine, alcohol, and recreational stimulants, can raise metanephrines. Do not stop medicines without medical advice.
Coffee, tea, energy drinks, chocolate, bananas, and vanilla-containing foods may influence results. Your doctor may advise limiting these before and during the collection.
Acute stress, vigorous exercise, pain, fever, or withdrawal from substances can elevate catecholamine metabolism and increase metanephrines temporarily.
Reduced kidney function can alter urinary excretion, and pregnancy can change hormone physiology. Your clinician will interpret results in these contexts.
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