Final answer:
The vanillylmandelic acid (VMA) test is performed to detect and monitor levels of vanillylmandelic acid in urine, which is a metabolite of catecholamines such as epinephrine and norepinephrine. High levels of VMA in the urine can indicate the presence of pheochromocytoma.
Step-by-step explanation:
The vanillylmandelic acid (VMA) test is performed to detect and monitor levels of vanillylmandelic acid in urine, which is a metabolite of catecholamines such as epinephrine and norepinephrine. This test is used specifically for the diagnosis of pheochromocytoma, a rare adrenal gland tumor that produces excessive amounts of catecholamines. High levels of VMA in the urine can indicate the presence of pheochromocytoma.