Observation of 24-hour urinary excretion rates of catecholamines and their metabolites is the test of choice to screen for pheochromocytoma. This procedure is best carried out during a paroxysmal spell. A two-fold rise in urinary catecholamines or metanephrine is highly suggestive of this disease. This test is not appropriate because the patient's clinical features do not suggest pheochromocytoma.