The Bottom Line: Determination of plasma metanephrine and normetanephrine, as measured by HPLC or RIA, is reliable for diagnosis of pheochromocytoma.
Petersenn. Diagnostic value of biochemical parameters in the differential diagnosis of an adrenal mass. Annals of the New York Academy of Sciences 2006 vol:1073 pg:348 -57
Metanephrines have been suggested as an alternative diagnostic tool. Previous studies have provided thresholds with sensitivities between 97% and 100% and specificities >85% and 96%. A 2006 study compared catecholamines and metanephrines in plasma and urine for the diagnosis of pheochromocytoma in patients with adrenal tumors.
TABLE 1. Optimal thresholds of various biochemical parameters and their sensitivity and specificity for the diagnosis of pheochromocytomas. Page 350
FIGURE 2. Sensitivity and specificity of various combinations of biochemical parameters for the diagnosis of pheochromocytomas page 351