Oral Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Accuracy of semi-quantitative quick cortisol assay with and without adrenocorticotropic hormone infusion during adrenal vein sampling (#211)

Felicity Stringer 1 , Pamela Franco 1 , Landy Wu 1 , Chris Preston 1 2 , Maresa Derbyshire 1 , Richard MacIsaac 1 3 , Eric Yong 4 , Benjamin Marginson 4 , Nirupa Sachithanandan 1 3
  1. Endocrinology, St Vincent's Hospital Melbourne, Melbourne, Victoria, Australia
  2. Endocrinology, Western Health, Melbourne, Victoria, Australia
  3. Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
  4. Radiology, St Vincent's Hospital Melbourne, Melbourne, Victoria, Australia

Background

Adrenal vein sampling (AVS) is the gold standard for diagnosing unilateral primary aldosteronism. Point-of-care cortisol assays such as the quick cortisol assay (QCA) are used to confirm accurate cannulation of the adrenal veins during the procedure and have improved AVS success rates [1].

Aim

The primary aim was to determine the accuracy of point-of-care QCA at semi-quantitatively assessing successful adrenal vein (AV) cannulation before and after ACTH (synacthen) infusion compared to laboratory cortisol measurements. Secondary aims were to assess the impact of adrenal vein cortisol levels and time of day on accuracy of QCA.

Methods

We performed a retrospective cohort study, reviewing the results of consecutive AVS procedures (n=37, total number of QCA samples=194) performed before and after ACTH infusion between October 2020 and December 2022 at our institution.

Results

The sensitivity of QCA pre-ACTH was 82%, increasing to 100% post-ACTH, with the specificity increasing from 58.9% pre-ACTH to 100% post-ACTH. The combined accuracy of QCA compared with laboratory cortisol measurements was 71% pre-ACTH and 100% post-ACTH (p<0.001, table 1). The number of additional samples taken pre-ACTH due to a false negative QCA result was 22, decreasing to 0 post-ACTH.  Pre-ACTH there were 23 false positive QCA results, resulting in 13 AVS procedures being prematurely abandoned with unsuccessful cannulation of the AV during basal AVS. Pre-ACTH, the accuracy of QCA was higher in the lowest and highest AV cortisol tertiles compared to the mid-tertile (p<0.001). Post-ACTH, the accuracy of QCA remained high regardless of AV cortisol levels. Time of day did not affect accuracy of the QCA.

Conclusion

Visual estimate of the gold nano-particle QCA are accurate in AVS performed with ACTH infusion, however are inaccurate during basal AVS. These results will help guide clinicians in appropriate clinical situations in which QCA should be used during AVS.

 

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