Validation of a serum immunoassay to measure progesterone and diagnose pregnancy in the West Indian manatee (Trichechus manatus)
The objective was to validate a high-sensitivity chemiluminescent assay of serum progesterone concentrations for pregnancy diagnosis in manatees. Assay analytical sensitivity was 0.1 ng/mL, with mean intra- and inter-assay coefficients of variation of 9.7 and 9.2%, respectively, and accuracy had a mean adjusted R2 of 0.98. Methods comparison (relative to Siemen's Coat-A-Count RIA) demonstrated r = 0.98, Deming regression slope of 0.95, and an intercept of 0.01. Based on ROC analysis, a progesterone concentration ≥0.4 ng/mL was indicative of pregnancy. Assay results were not significantly altered by two freeze-thaw cycles of samples. Characteristic progesterone concentrations during pregnancy were Months 1-4 (1.7-4.7 ng/mL), 5-8 (∼1.0 ng/mL), and 10 and 11 (0.3-0.5 ng/mL), whereas two late-pregnant females with impending abortion had progesterone concentrations of 0.1 ng/mL. Among pregnant females, maximum progesterone concentrations occurred in autumn (3.9 ± 1.8 ng/mL), and were greater during all seasons than concentrations in non-pregnant females (0.1-0.2 ng/mL). Progesterone concentrations were also significantly higher in pregnant females than in non-pregnant females and males. This highly sensitive, specific, and diagnostic assay will be valuable for monitoring pregnancy and abortion in manatees.
Assay validation, Manatee, Pregnancy diagnosis, Progesterone, Reproduction
Tripp, K. M., J. P. Verstegen, C. J. Deutsch, R. K. Bonde, M. Rodriguez, B. Morales, D. L. Schmitt, and K. E. Harr. "Validation of a serum immunoassay to measure progesterone and diagnose pregnancy in the West Indian manatee (Trichechus manatus)." Theriogenology 70, no. 7 (2008): 1030-1040.