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Successful use of a benchtop fluorescent enzyme immunoassay analyzer to measure serum cortisol concentration as a screening test for hypoadrenocorticism in dogs

Bacon, Jessica; Graham, Peter A.; Hrovat, Alenka; Kilpatrick, Scott; Mann, Nicholas O.; Swales, Harry


Jessica Bacon

Professor of Veterinary Clinical Pathology and Endocrinology

Alenka Hrovat

Scott Kilpatrick

Nicholas O. Mann

Harry Swales


OBJECTIVE To assess the diagnostic performance of a benchtop fluorescent enzyme immunoassay analyzer (AIA-360; Tosoh Bioscience Inc) for the measurement of serum cortisol concentration as a screening test for hypoadrenocorticism in dogs. ANIMALS 173 client-owned dogs (20 with hypoadrenocorticism and 153 with nonadrenal illness). PROCEDURES Medical records of all dogs that underwent an ACTH stimulation test between June 2015 and October 2019 were reviewed retrospectively. Dogs were excluded if the ACTH stimulation test was performed on the basis of a suspicion of hypercortisolism, serum cortisol concentrations were measured using an analyzer other than the one assessed in the present study, or dogs had received medication known to affect the pituitary-adrenal axis in the 4 weeks1,2 preceding ACTH stimulation testing. The diagnostic performance of the benchtop analyzer was evaluated by calculating sensitivity, specificity, and likelihood ratios at various cutoff points. RESULTS Serum resting cortisol cutoff point concentrations of 0.8 μg/dL (22 nmol/L), 1 μg/dL (28 nmol/L), and 2 μg/dL (55 nmol/L) had a sensitivity of 100%. An optimal serum resting cortisol cutoff point of 0.58 μg/dL (16 nmol/L) had a sensitivity, specificity, and positive and negative likelihood ratios of 100%, 97%, and 30.6 and 0.0, respectively. CLINICAL RELEVANCE Findings indicated that previously derived cutoff points could be used with excellent sensitivity to exclude hypoadrenocorticism in this population of dogs when serum cortisol concentration was measured with the evaluated benchtop analyzer. An ACTH stimulation test may need to only be performed to diagnose hypoadrenocorticism if resting serum cortisol concentration is ≤ 0.58 μg/dL when measured with the evaluated benchtop analyzer.

Journal Article Type Article
Acceptance Date Oct 3, 2022
Online Publication Date Oct 25, 2022
Publication Date Jan 1, 2023
Deposit Date Nov 2, 2022
Journal Journal of the American Veterinary Medical Association
Print ISSN 0003-1488
Electronic ISSN 1943-569X
Publisher American Veterinary Medical Association (AVMA)
Peer Reviewed Peer Reviewed
Volume 261
Issue 1
Pages 111-117
Keywords General Veterinary
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