Description
Metanephrine and normetanephrine are metabolic products of epinephrine and norepinephrine, the adrenal medullary hormones secreted by pheochromocytomas. Because secretion is usually episodic, plasma catecholamines (of epinephrine and norepinephrine) drawn during an asymptomatic period may be normal, while total metanephrines collected over 24 Hrs would be abnormal. On the other hand, a tumour could be intermittently active, but secrete over a full 24- hour period total metanephrines within normal limits.
Indications
This test is used to evaluate the presence of abnormal catecholamine production, metanephrines may be elevated when VMA and catecholamines are within normal limits; diagnose pheochromocytoma, neuroblastoma, and ganglioneuroblastoma.
Sample Type, Quantity & Conditions
30 ml of 24 Hrs urine 2 - 8°C
Special Precautions
Adjust pH to 1.0 with HCl.
Normal Range
< 1000 μg/24 Hrs
