Chromogranin A is an accurate general marker for neuroendocrine tumors—most patients with pheochromocytomas or paragangliomas have high plasma concentrations of this marker. Grossrubatscher and colleagues, therefore, evaluated the diagnostic value of chromo granin A compared with that of urinary levels of catecholamines and their metabolites in patients with pheochromocytomas. The role of chromogranin A in the assessment of surgical cure of pheochromocytoma was also investigated. The authors observed 21 consecutive patients who had pheochromocytomas at initial presentation or who had experienced postsurgical relapse, plus one patient who was followed up for malignant pheo chromocytoma. A control group of 20 patients in whom pheochromocytoma was suspected, but not subsequently diagnosed, was also evaluated. No patient with pheochromocytoma had normal urinary levels of both meta nephrine and normetanephrines. Measurement of both metanephrine and normetanephrine, therefore, had a sensitivity of 100% in identifying pheo chromocytoma. Overall, 17 patients were assessed before and after surgery; post operatively, 14 of these patients had normal metanephrine and normeta nephrine levels, and 12 had normal chromo granin A levels. At initial presentation, 20 patients with pheo chromocytomas had high chromogranin A levels. The two patients with normal chromo granin A levels had high levels of cate cholamines and their metabolites. Chromogranin A has a sensitivity of 91% in identifying patients with pheochromocytomas; measurement of both chromogranin A and cate cholamines increases the sensitivity to 100%. A decrease in chromogranin A levels might also help to demonstrate cure after surgery.