Comparison of two methods for measurement of equine adrenocorticotropin.
Abstract: Accurate measurement of equine adrenocorticotropin (ACTH) is important for the diagnosis of equine pituitary pars intermedia dysfunction (PPID). Several radioimmunoassays (RIAs) and chemiluminescent immunoassays (CIAs) are used for measurement of ACTH concentration in horses; whether these methods yield similar results across a range of concentrations is not determined. We evaluated agreement between a commercial RIA and CIA. Archived plasma samples ( n = 633) were measured with both assays. Correlation between the 2 methods was moderate ( r = 0.49, p < 0.001). Bland-Altman analysis revealed poor agreement, with a proportional bias and widening limits of agreement with increasing values. Poor agreement between assays was also observed when evaluating plasma samples with concentrations at or below the recommended diagnostic cutoff value for PPID testing. The lack of agreement suggests that measurements obtained should not be considered interchangeable between methods.
Publication Date: 2017-12-28 PubMed ID: 29284383PubMed Central: PMC6505866DOI: 10.1177/1040638717752216Google Scholar: Lookup
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- Comparative Study
- Journal Article
- Validation Study
- Adrenal
- Analytical Methods
- Biochemistry
- Clinical Pathology
- Clinical Study
- Comparative Study
- Correlation Analysis
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Equine Diseases
- Equine Health
- Hormones
- Horses
- Immunoassay
- Laboratory Methods
- Physiology
- Pituitary Pars Intermedia Dysfunction
- Plasma
- Veterinary Medicine
- Veterinary Research
Summary
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This research compares the accuracy and similarity of results from two different assays (radioimmunoassays and chemiluminescent immunoassays) used to measure equine adrenocorticotropin (ACTH), a hormone important in diagnosing pituitary dysfunction in horses. The findings suggest significant discrepancies between the two methods, implying that they should not be considered interchangeable in clinical practice.
Introduction
- This study revolved around equine adrenocorticotropin (ACTH), a hormone that plays a significant role in the diagnosis of equine pituitary pars intermedia dysfunction (PPID), a common endocrine disorder in horses.
- ACTH levels in horses are typically measured through radioimmunoassays (RIAs) and chemiluminescent immunoassays (CIAs). The study sought to establish if these two methods yield similar results across varied ACTH concentrations.
Methods
- A total of 633 archived plasma samples were used in this study. The samples were measured using both the RIA and CIA methods.
- Bland-Altman statistical analysis was carried out to ascertain the level of agreement between the two assays. This type of analysis gives a visual representation of the averaging bias, as well as the agreement limits.
Results
- There was a moderate correlation between the two types of assays ( r = 0.49, p < 0.001).
- However, the Bland-Altman analysis revealed poor agreement. A proportional bias was identified, meaning the difference between the two methods varied depending on the magnitude of the measurement. Furthermore, the limits of agreement widened with increasing ACTH values.
- This disparity was also noticed when dealing with plasma samples with ACTH concentrations at or below the recommended diagnostic cutoff value for PPID testing.
Conclusion
- The research found that there is a lack of agreement between RIA and CIA methods for measuring ACTH concentration in horses. This means that the values obtained from these assays cannot be used interchangeably.
- These findings hold significant implications for further studies and for clinical practice in the diagnosis and measurement of PPID. The choice of method for measuring ACTH levels may, therefore, significantly impact the reliability and comparability of research findings or clinical test results.
Cite This Article
APA
Banse HE, Schultz N, McCue M, Geor R, McFarlane D.
(2017).
Comparison of two methods for measurement of equine adrenocorticotropin.
J Vet Diagn Invest, 30(2), 233-237.
https://doi.org/10.1177/1040638717752216 Publication
Researcher Affiliations
- Department of Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada (Banse).
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN (Schultz, McCue).
- College of Sciences, Massey University, Manawatu, NZ (Geor).
- Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (McFarlane).
- Department of Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada (Banse).
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN (Schultz, McCue).
- College of Sciences, Massey University, Manawatu, NZ (Geor).
- Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (McFarlane).
- Department of Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada (Banse).
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN (Schultz, McCue).
- College of Sciences, Massey University, Manawatu, NZ (Geor).
- Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (McFarlane).
- Department of Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada (Banse).
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN (Schultz, McCue).
- College of Sciences, Massey University, Manawatu, NZ (Geor).
- Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (McFarlane).
- Department of Veterinary Clinical and Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada (Banse).
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN (Schultz, McCue).
- College of Sciences, Massey University, Manawatu, NZ (Geor).
- Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (McFarlane).
MeSH Terms
- Adrenocorticotropic Hormone / blood
- Animals
- Female
- Horse Diseases / blood
- Horse Diseases / diagnosis
- Horses / blood
- Immunoassay / veterinary
- Male
- Pituitary Diseases / blood
- Pituitary Diseases / diagnosis
- Pituitary Diseases / veterinary
- Pituitary Gland, Intermediate
- Reference Values
- Reproducibility of Results
Conflict of Interest Statement
The authors declared no potential conflicts of interest with respect to the
research, authorship, and/or publication of this article.
References
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Citations
This article has been cited 4 times.- Hinrichsen SL, Yuen KY, Dryburgh EL, Bertin FR, Stewart AJ. Short-Term Effects of Temperature and Thyrotropin-Releasing Hormone Stimulation on Adrenocorticotropin Stability in Horses. Animals (Basel) 2022 Jan 28;12(3).
- Thane K, Uricchio C, Frank N. Effect of early or late blood sampling on thyrotropin releasing hormone stimulation test results in horses. J Vet Intern Med 2022 Mar;36(2):770-777.
- Kam YN, McKenzie K, Coyle M, Bertin FR. Repeatability of a thyrotropin-releasing hormone stimulation test for diagnosis of pituitary pars intermedia dysfunction in mature horses. J Vet Intern Med 2021 Nov;35(6):2885-2890.
- Potier JF, Louzier V. Evaluation of stress markers in horses during hippotherapy sessions in comparison to being ridden by beginners. Anim Welf 2023;32:e10.
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