Episodic sweating, palpitations and hypertension suggest phaeochromocytoma. Metanephrines (plasma free metanephrine and normetanephrine) are the most sensitive and specific biochemical test. Urinary catecholamines alone and VMA are less accurate (the sources pair urine catecholamines with metanephrines). CT is done only after biochemical confirmation, to localise the tumour.