18-hydroxycorticosterone, 18-hydroxycortisol, and 18-oxocortisol in the diagnosis of primary aldosteronism and its subtypes.

[adrenal incidentaloma]

Diagnosis of primary aldosteronism (PA ) is made by screening , confirmation testing , and subtype diagnosis (computed tomography scan and adrenal vein sampling ). However , some tests are costly and unavailable in most hospitals .The aim of the study was to evaluate the role of serum 18 -hydroxycorticosterone (s 18 OHB ), urinary and serum 18 -hydroxycortisol (u- and s 18 OHF ), and urinary and serum 18 -oxocortisol (u- and s 18 oxoF ) in the diagnosis of PA and its subtypes , aldosterone-producing adenoma (APA ) and bilateral adrenal hyperplasia (BAH ).The study included 62 patients with low -renin essential hypertension (EH ), 81 patients with PA (20 APA , 61 BAH ), 24 patients with glucocorticoid-remediable aldosteronism , 16 patients with adrenal incidentaloma , and 30 normotensives .We measured s 18 OHB , s 18 OHF , and s 18 oxoF before and after saline load test (SLT ) and 24 -h u 18 OHF and u 18 oxoF .PA patients displayed significantly higher levels of s 18 OHB , u 18 OHF , and u 18 oxoF compared to EH and normal subjects ; APA patients displayed s 18 OHB , u 18 OHF , and u 18 oxoF levels significantly higher than BAH patients . Similar results were obtained for s 18 OHF and s 18 oxoF . SLT significantly reduced s 18 OHB , s 18 OHF , and s 18 oxoF in all groups , but steroid reduction was much less for APA patients compared to BAH and EH . The s 18 OHB /aldosterone ratio after SLT more than doubled in EH but remained unchanged in APA patients .u 18 OHF , u 18 oxoF , and s 18 OHB measurements in patients with a positive aldosterone /plasma renin activity ratio correlate with confirmatory tests and adrenal vein sampling in PA patients . If verified , these steroid assays would refine the diagnostic workup for PA .