|
1
|
Banse HE, Schultz N, McCue M, Geor R, McFarlane D. Comparison of two methods for measurement of equine adrenocorticotropin. J Vet Diagn Invest 2017; 30:233-237. [PMID: 29284383 DOI: 10.1177/1040638717752216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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.
Collapse
Affiliation(s)
- Heidi E Banse
- 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)
| | - Nichol Schultz
- 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)
| | - Molly McCue
- 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)
| | - Ray Geor
- 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)
| | - Dianne 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)
| |
Collapse
|