Accuracy of semi-quantitative gold nanoparticle-based quick cortisol assay with and without adrenocorticotropic hormone infusion during adrenal vein sampling

Adrenal vein sampling (AVS) is the gold standard for diagnosing unilateral primary aldosteronism. Point-of-care rapid cortisol assays such as the gold nanoparticle based quick cortisol assay (QCA) are used to confirm accurate cannulation of the adrenal veins during the procedure and have improved AVS success rates. In this retrospective cohort study, we reviewed the results of consecutive AVS procedures (n = 37) performed with and without ACTH (synacthen) infusion between October 2020 and December 2022 at our institution. We compared (1) the accuracy of point-of-care QCA at semi-quantitatively assessing successful adrenal vein cannulation before and after ACTH infusion when compared with selectivity index based on laboratory cortisol measurements, (2) accuracy of QCA based on peripheral and adrenal vein cortisol levels and (3) the impact of time of day on the accuracy of QCA. We found the accuracy of QCA compared with formal laboratory cortisol measurements was 71% pre-ACTH and 100% post-ACTH (p-value < 0.001). Pre-ACTH, the accuracy of QCA was higher in the lowest (28-257 nmol/L) and highest (466-25130 nmol/L) adrenal vein cortisol tertiles compared to the mid-tertile. Post-ACTH, the accuracy of QCA remained high regardless of adrenal vein cortisol levels. Time of day did not affect the accuracy of the QCA. We conclude that during basal AVS subjective, visual estimates of adrenal vein cortisol levels using the QCA semi-quantitively should not be solely relied upon to guide catheter placement. These results will help guide clinicians in the appropriate clinical situations in which QCA should be used during AVS.