Analysis index

10 ml of 24-hour urine.

Storage at 4°C (also during collection).

Please refer to section “Catecholamines in urine”

Metanephrine: 74 – 297 µg/24 hours
Normetanephrine: 105 – 354 µg/24 hours

Suspicion of secondary hypertension, diagnosis and monitoring of pheochromocytoma or pheochromocytoma-paraganglioma syndrome, screening of MEN 2A, neurofibromatosis type 1, Hippel-Lindau syndrome and incidentalomas, suspicion of neuroblastomas (in connection with vanillic- and homovanillic mandelic acid) and ganglioneuroma.

Refrain from coffee, tea, nicotine, alcohol, chocolate, bananas, eggs and nuts for 2 – 3 days prior to the test. As far as tenable, all medication should be discontinued 7 – 14 days before the test. Theophylline, MAO-inhibitors, phenothiazine, methyldopa, and levodopa can be responsible for an increased catecholamine excretion for up to two weeks and should definitely be discontinued. The same goes for diuretics, alpha- and beta-receptor blockers, vasodilators, calcium antagonists, angiotensin-II antagonists and ACE inhibitors. Clonidine (Catapressan®) should be discontinued, where possible. A strong symphathicus stimulation caused by hypoglycemia, physical exertion or an increased intracranial pressure, may also lead to an increased catecholamine excretion.

As the determination of metanephrine and normetanephrine in the urine reflects the catecholamine excretion that has been integrated over 24 hours, the sensitivity is higher, compared to that in plasma, especially in tumors, which only secrete catecholamines periodically. It should be noted, that missing catecholamine excretion however, does not rule out pheochromocytoma/paraganglioma, as there are also non-secreting variants, which are especially seen in older people. In addition, the production of dopamine should be considered for clinically inapparent pheochromocytomas/paragangliomas; thus in these cases dopamine or its degradation product 3-methoxytyramine (only in plasma) should be determined.