ACTH stimulation test and computed tomography are useful for differentiating the subtype of primary aldosteronism.

The diagnostic steps for primary aldosteronism (PA) include case screening tests, confirmatory tests, and localization. The aim of this study was to identify useful confirmatory tests and their cut-off values for differentiating the subtype of primary aldosteronism, especially in unilateral PA, such as aldosterone-producing adenoma, and bilateral PA, such as idiopathic hyperaldosteronism. Seventy-six patients who underwent all four confirmatory tests, the captopril-challenge test (CCT), furosemide upright test (FUT), saline infusion test (SIT), and ACTH stimulation test (AST), and who were confirmed to have an aldosterone excess by adrenal venous sampling (AVS) were recruited.