Which test is used as a confirmatory test after an initial positive screen for pheochromocytoma?

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Multiple Choice

Which test is used as a confirmatory test after an initial positive screen for pheochromocytoma?

Explanation:
Screening with metanephrines is highly sensitive, but a positive result needs a confirmatory test that reflects steady tumor activity rather than brief spikes. Measuring metanephrines in a 24-hour urine collection captures ongoing production of these metabolites and tends to have higher specificity, helping distinguish true pheochromocytoma from other causes of elevated catecholamines or false positives. Urinary VMA, while an older option, is less reliable due to variability from diet and other factors. Serum catecholamines can vary with acute stress and aren’t as dependable for confirmation. So, the 24-hour urine metanephrines test best confirms pheochromocytoma after an initial positive screen.

Screening with metanephrines is highly sensitive, but a positive result needs a confirmatory test that reflects steady tumor activity rather than brief spikes. Measuring metanephrines in a 24-hour urine collection captures ongoing production of these metabolites and tends to have higher specificity, helping distinguish true pheochromocytoma from other causes of elevated catecholamines or false positives. Urinary VMA, while an older option, is less reliable due to variability from diet and other factors. Serum catecholamines can vary with acute stress and aren’t as dependable for confirmation. So, the 24-hour urine metanephrines test best confirms pheochromocytoma after an initial positive screen.

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