[Differential diagnosis of primary aldosteronism by measurement of hybrid steroids using mass spectrometry].

Primary aldosteronism (PA), characterized by the autonomous hypersecretion of aldosterone, is the most common cause of secondary hypertension. Patients with PA have a higher risk of cardiovascular morbidity than essential hypertension. The two common subtypes of PA, aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA), should be differentiated, because the former is an indication for adrenalectomy, and the latter is treated by medication. 18-Hydroxycortisol and 18-oxocortisol, known as hybrid steroids, have been recognized as markers for the differentiation of aldosterone-producing adenoma and rare glucocorticoid remediable hyperaldosteronism from other subtypes of PA. Hybrid steroids have been measured using immunoassays such as enzyme-linked immunoassays; however, immunoassays for hybrid steroids are not widely used. Recently, liquid chromatography-tandem mass spectrometry (LC-MS/MS) for hybrid steroids was developed. The ability to measure hybrid steroids using LC-MS/MS will be useful for the differential diagnosis of subtypes of PA.