Determination of three C18‐oxygenated steroids in adrenal lesion segments in primary aldosteronism by super‐selective adrenal venous sampling and LC/ESI–MS/MS

Abstract Super‐selective adrenal venous sampling (ssAVS) can collect the adrenal tributary venous blood in the aldosterone (ALD)‐hypersecreting segments in primary aldosteronism. The concentrations of the C18‐oxygenated steroids, especially 18‐oxocortisol (18‐oxoF), in the lesion segments might be more useful indices than those in the peripheral or adrenal central veins (current candidate indexes) for the differential diagnosis of unilateral ALD‐producing adenoma (APA) and bilateral adrenal hyperplasia (BAH). To verify this hypothesis, we developed a liquid chromatography/electrospray ionization‐tandem mass spectrometry (LC/ESI–MS/MS) method for simultaneously quantifying ALD, 18‐oxoF and 18‐hydroxycortisol in the adrenal tributary venous serum sample collected by ssAVS (ssAVS serum) and compared their concentrations between APA and BAH patients. Only deproteinization was required for a 10 μl sample prior to the LC/ESI–MS/MS analysis. Endogenous corticoids did not interfere with the quantifications, and the intra‐assay and interassay precisions (≤ 8.3%) and accuracies (94.2–102.7%) were acceptable. The clinical study revealed that the 18‐oxoF concentration was significantly higher in the ALD‐producing tumor tissues (from APA patients) than in the hyperplastic tissues (from BAH patients). However, in conclusion, the 18‐oxoF concentration in the ssAVS serum sample can be a rough indication but cannot be decisive for the differential diagnosis between APA and BAH owing to the significant individual difference.