Re‐evaluation of the low‐dose dexamethasone suppression test in dogs. (11th September 2022)

• Record Type: Journal Article
• Authors: Lim, L.; Hulsebosch, S. E.; Gilor, C.; Reagan, K. L.; Kopecny, L.; Maggiore, A. D.; Phillips, K. L.; Kass, P. H.; Vernau, W.; Nelson, R. W.
• Is Part Of: Journal of small animal practice. Volume 64:Number 1(2023)
• Page Start: 12
• Page End: 20
• Publication Date: 2022-09-11
• Subjects: Veterinary medicine -- Periodicals; Veterinary Medicine -- Periodicals; 636.089
• DOI: 10.1111/jsap.13553
• Languages: English
• ISSNs: 0022-4510

Abstract

Abstract : Objectives: This study aims to re‐evaluate the low‐dose dexamethasone suppression test 8‐hour cortisol cut‐point for the diagnosis of hypercortisolism in dogs using a solid‐phase, competitive chemiluminescent enzyme immunoassay. Materials and Methods: Twenty‐seven client‐owned dogs with naturally occurring hypercortisolism and 30 healthy control dogs were prospectively recruited. Performance of the low‐dose dexamethasone suppression test was assessed using sensitivity, specificity and a receiver operating characteristic curve compared to a clinical diagnosis of hypercortisolism including response to treatment. Results: Twenty‐four dogs were diagnosed with pituitary‐dependent hypercortisolism and three with adrenal‐dependent hypercortisolism. In 30 healthy control dogs, 8‐hour post‐dexamethasone cortisol concentrations ranged from 5.5 to 39 nmol/L. A receiver operating characteristic curve curve constructed from the 8‐hour post‐dexamethasone cortisol concentrations of hypercortisolism and control dogs demonstrated that the most discriminatory cut‐point was more than 39 nmol/L with sensitivity of 85.2% (95% confidence interval, 67.5% to 94.1%) and specificity of 100% (95% confidence interval, 88.7% to 100.0%) and an area under the curve of 0.963. Clinical Significance: The optimal cut‐point of more than 36 nmol/L proposed by this study is similar to the currently accepted 8‐hour cortisol concentration cut‐point for diagnosing hypercortisolism when using a solid‐phase, competitive chemiluminescent enzyme immunoassay.