title: Urinary normetanephrine and metanephrine measured by radioimmunoassay for the diagnosis of pheochromocytoma: utility of 24-hour and random 1-hour urine determinations.
abstract: To validate the clinical usefulness of recently developed normetanephrine (NM) and metanephrine (M) RIA for the diagnosis of pheochromocytoma, urinary excretion of catecholamines and these metabolites were determined in 30 normal subjects, 40 patients with essential hypertension, 30 patients who were suspected to have but ultimately proven not to have a pheochromocytoma (pheochromocytoma-suspect), and 31 patients with a surgically verified pheochromocytoma. Abnormally high catecholamine excretion (epinephrine plus norepinephrine) was found in patients with pheochromocytoma compared with that in the normal subjects and the essential hypertension group. However, 3 of 31 patients with pheochromocytoma had urinary catecholamine excretion that overlapped the values in the pheochromocytoma-suspect group. Both urinary NM and M excretion also were elevated in patients with pheochromocytoma, but in 4 of 31 patients with pheochromocytoma urinary M excretion was within the range found in 1 or more of the other groups. Total M (NM plus M) excretion of more than 5485 nmol/day (as NM) was found in all patients with pheochromocytoma, and all patients had values that were higher than the highest values in the normal subjects or the patients with no evidence of pheochromocytoma. To save time and simplify the diagnostic work-up of patients suspected of having a pheochromocytoma, we also determined the NM and M concentrations in randomly voided 1-h urine samples in 24 patients with pheochromocytomas, 31 patients with essential hypertension, and 16 normal subjects. Abnormally high total M excretion was found in all patients with pheochromocytomas, and there was no overlap with the values in the patients with essential hypertension or the normal subjects. We conclude that total M measurements in both 24-h and random 1-h urine samples are useful in diagnosing pheochromocytomas.
authors.affiliation: Third Department of Internal Medicine, Faculty of Medicine, Kumamoto University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Oishi
authors.forename: M
authors.initials: M
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: T
authors.initials: T
authors.lastname: Sato
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000652:urine; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm; D004837:Epinephrine / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000652:urine; D008297:Male; D008676:Metanephrine / Q000652:urine*; D008875:Middle Aged; D009647:Normetanephrine / Q000652:urine*; D010673:Pheochromocytoma / Q000175:diagnosis* / Q000652:urine; D013048:Specimen Handling
chemical_list: D009647:Normetanephrine; D008676:Metanephrine; D004837:Epinephrine