Why would a doctor order a 24 hour urine for catecholamines test?
It’s a screening test for a type of tumor called pheochromocytoma. This accounts for less than 1% of patients with high blood pressure. If a physician suspects that a patient falls into a group that is at risk for pheochromocytoma, this 24 hour collection of urine will allow the physician to determine if there is abnormally high production of these catecholamines (the pheochromocytoma produces these chemicals like norepinephrine and similar hormones). If the test comes back positive, then the next thing is to localize where the tumor is located and the literature has traditionally noted that 90% of these are associated with the adrenal aka suprarenal glands. There are a number of imaging methods one can use to localize them. It’s important to be able to make this unusual diagnosis because it is one of the uncommon causes of high blood pressure that can be cured definitively by resecting the tumor. Please note that this is a rather uncommon entity that is not encountered all that often
