Table 2. Immunoassays used to evaluate fecal samples from an adrenocorticotrophic hormone challenge (ACTH).

Results indicated a high correlation for both validation methods used; parallel displacement curves and recovery of the standards. Cross-reactivities of each assay with associated glucocorticoid metabolites are indicated as well as the optimal dilution used for samples on each assay.

Assay	Product Information	Parallelism	Recovery		Cross-reactivities	Dilution
		Correlation coefficient	Equation	Correlation coefficient
Cortisol EIA (single antibody)	R4866 supplied by C.J. Munro, University of California, Davis, CA, USA	r = 0.98	y = 0.88x + 89.17	r = 0.98	cortisol at 100%, prednisolone (9.9%), prednisone (6.3%), cortisone (5%), other metabolites at <1%	1:200
Cortisol RIA (double antibody)	Coat-A-Count, PITKCO-9, 2010-10-21, Siemens, Los Angeles, CA, USA	r = 0.98	y = 1.40x +0.56	r = 0.99	prednisolone (76%), 11-deoxycortisol (11.4%), methylprednisone (11%), prednisone (2.3%), betamethasone (1.6%), other metabolites at <1%	1:8
Corticosterone EIA (double antibody)	R0006 supplied by C.J. Munro, UC Davis, Davis, CA, USA	r = 0.96	y = 0.82x + 15.27	r = 0.99	corticosterone 100%, deoxycorticosterone 14.25%, progesterone 2.65%, other metabolites at <1%	1:64
Corticosterone RIA (double antibody)	I125 kit ImmuChem, MP Biomedicals, LLC Diagnostics Division Orangeburg, NY, USA	r = 0.95	y = 1.31x + 51.92	r = 0.99	corticosterone 100%, other metabolites at <1%	1:200