Published by Bioscientifica Ltd. Printed in Great Britain © 2020 European Society of Endocrinology https://eje.bioscientifca.com https://doi.org/10.1530/EJE-19-0923 European Journal of Endocrinology 182:2 C5–C7 W J Inder Porcine ACTH stimulation test Long-acting porcine sequence ACTH in the diagnosis of adrenal insufficiency: a cost-effective alternative to the ACTH 1–24 test Warrick J Inder Department of Diabetes and Endocrinology, Princess Alexandra Hospital, and PA-Southside Clinical Unit, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia Abstract While the ACTH 1–24 test has some well-documented shortcomings, it is the most widely used test to diagnose primary and secondary adrenal insufciency. However, this synthetic ACTH preparation is not readily available in some countries. Research from India has demonstrated that using a long-acting porcine sequence ACTH has similar diagnostic performance to ACTH 1–24 at around 25% of the cost. This may allow access to a robust test for adrenal insufciency to developing countries and potentially allow thousands of patients to be identifed and appropriately treated. The ACTH 1–24 test, also known as the short Synacthen® test or the Cosyntropin test depending on your country of origin, was frst used as a test of hypothalamic-pituitary adrenal axis function in the 1960s (1). Across the ensuing decades, debate has raged about many issues such as whether it is an accurate enough measure for secondary adrenal insuffciency (2), what dose of ACTH 1–24 should be used (2), optimal timing of blood samples (3), the effect of different cortisol assays on diagnostic cut-offs (4, 5) and thresholds for basal cortisol which might make such a test unnecessary (6). As time and further research have progressed, we now have answers to most of these questions, providing endocrinologists with a ‘reasonably’ clear picture of the strengths and limitations of the ACTH 1–24 test. However one issue which I suspect most endocrinologists practising in developed countries have never needed to consider is the cost and availability of ACTH 1–24 . The recently published paper by Nair et al. from Thiruvananthapuram, India reports the results of a comparative study between ACTH 1–24 and long-acting porcine sequence ACTH known as Acton Prolongatum® in the diagnosis of adrenal insuffciency (7). ACTH 1–24 is not marketed in India, and while the authors managed to access this, the cost was 14 times higher per dose of Synacthen® compared to Acton Prolongatum®. They cite several other studies, also from India, where the cortisol response to Acton Prolongatum® has been reported. For example, Gundguruthy et al. examined the cortisol response in healthy volunteers and patients with adrenal insuffciency (8), while Wagmode et al. examined healthy volunteers but also used the ACTH 1–24 test as a comparator (9). Thus, there is a growing body of literature from India which attests to the safety and effcacy of Acton Prolongatum® as an alternative ACTH stimulation test – with Nair et al. being the frst to undertake a comprehensive comparative study in adults with suspected adrenal insuffciency and publish their data in an international Endocrine journal (7). Their results demonstrate that 30 IU of Acton Prolongatum® may be a slightly more potent Correspondence should be addressed to W J Inder Email Warrick.Inder@health.qld. gov.au European Journal of Endocrinology (2020) 182, C5–C7 Commentary Downloaded from Bioscientifica.com at 07/24/2020 09:40:49AM via free access