The test is a plasma metanephrine test and it has the highest sensitivity (96%) for detecting a pheochromocytoma. However, urine tests are even more specific but a pain to do (collecting urine more than once) - so to rule in or out the possiblity of a pheochromocytoma, doctors usually order the blood test first., Then imaging shows where the tumor is, etc. I can't say if your doctor is going straight to the scan because he is pretty sure that's what you have but that's a guess...Or maybe he ran the blood work but didn't discuss it with you yet? Anyway, good luck. Nobody wants to have to have a tumor - but if you have one, these are usually very small, benign , treatable so your problem could likely be cured.