Diagnostic studies-pheochromocytoma and paraganglioma

(JCEM 2014;99:1915)

• 24° urinary fractionated metanephrines: 98% Se, 98% Sp. Screening test of choice if low-risk (b/c false ⊕ with severe illness, renal failure, OSA, labetalol due to assay interference, acetaminophen, TCAs, medications containing sympathomimetics).
• Plasma fractionated metanephrines: 97% Se, 91% Sp. Screening test of choice if high risk, but ↑ rate of false ⊕ in low-prevalence population. False ⊕ rate lower if patient supine for 30 min (estimated 2.8× ↑ false ⊕ if seated).
• Adrenal CT or T2-weighted MRI; PET for known metastatic disease or to localize nonadrenal mass but usually easy to find; consider MIBG scintigraphy if CT/MRI ⊖
• Consider genetic testing in all Pts (J Intern Med 2019;285:187)