Figure 2. Algorithm showing use of biochemical tests for diagnosis of pheochromocytoma.Values in parentheses indicate expected numbers of patients with and without pheochromocytoma at different steps during diagnosis, assuming a 2% incidence of the tumor in a population of 1000 patients undergoing testing for clinically suspected pheochromocytoma (that is, 20 patients with and 980 without pheochromocytoma). CT = computed tomography; MRI = magnetic resonance imaging. * For continuation of the algorithm, see Figure 4.