Postoperatively his plasma-free metanephrines
showed a normetanephrine still elevated at 295 (n < 148), and the metanephrine
and chromogranin A were normal.
Elevated plasma metanephrine
levels are also consistent.
A comparison of biochemical tests for pheochromocytoma: measurement of fractionated plasma metanephrines
compared with the combination of 24-hour urinary metanephrines
001) values for plasma metanephrine
than samples obtained from patients after 30 min of supine rest (data not shown).
The most common biochemical approaches used to detect pheochromocytoma are measurements of metanephrines
(MADs)  or catecholamines in plasma or urine, although some studies have advocated the use of chromogranin (1) or platelet catecholamines (2).
2 nmol/L (400 ng/L) or of plasma free metanephrine
Until the spring of 2004, the only source of commercially available urine metanephrine
calibrators in the US was Bio-Rad.
Measurement of plasma metanephrine
and normetanephrine concentrations has recently been acknowledged as one of the leading tests for the diagnosis of the neuroendocrine tumor, pheochromocytoma (1).
Evaluation of a clinically inapparent adrenal mass led to tests for pheochromocytoma (1) with findings of increased urinary metanephrine
and normetanephrine but normal plasma metanephrines
dehydroepiandrosterone sulfate (DHEA-S), serum baseline 17-hydroxyprogesterone (17-0HP), urinary metanephrine
, normetanephrine, vanilylmandelic acid (VMA) excretion, low-dose 2 mg dexamethasone suppression tests, plasma aldosterone and renin activity.
The endocrine studies (urinary metanephrine
, vanillylmandelic acid, homovanillic acid and dopamine) are useful in patients with symptoms of cathacolamine-secreting tumors.
In a suspected case of adrenal neoplasm, or in elucidating the cause of secondary hypertension in addition to excluding pheochromocytoma by serum metanephrine
or VMA in urine, cortisol production should also be measured by either serum cortisol levels or a low-dose dexamethasone suppression test.