Adrenal vein sampling (AVS),as the gold standard of subtype diagnosis for primary aldosteronism,can directly detect the hormone concentration in adrenal vein by adrenal vein cannulation.Adrenal tumor can be categorized into no function adenoma,adrenal carcinoma,aldosterone producing adenoma (APA),cortisol producing adenoma (CPA) and pheochromocytoma.Traditionally,peripheral blood hormone testing and image examination were performed to make functional diagnosis of adrenal tumor,which exhibits low specificity and sensitivity.On the contrary,AVS can help make a distinct lateralization diagnosis according the aldosterone concentration of each gland,even in the condition of bilateral adrenal tumor and early stage tumor,which is difficult to make functional lateralization diagnosis by traditional methods.AVS can be categorized into simultaneous sampiing and sequencing sampling,according to the order of sampling.According to using adrenocorticotropic hormone (ACTH) or not,AVS can be categorized into no stimulus sampling and post-stimulus sampling.