Surgery General d5775df2 Most sensitive test for diagnosing pheochromocytoma is : A MRI B 24 hour urinary xma C MIBG scan D Plasma free metanephrines High-Yield Explanation Plasma free metaneprines is the most sensitive test. 24 hour urinary VMA is used for screening. MRI is the IOC for extraadrenal pheochromocytomos.