Comparison of three progesterone quantification methods using blood samples drawn from bitches during the periovulatory phase

Background and Aim: Measuring blood progesterone (P4) concentration has become an essential diagnostic tool in small animal reproductive medicine. Methods enabling precise and rapid on-site measurements are in high demand, especially for the optimization of breeding management in bitches. This study aimed to compare two commercial on-site methods (Speed (TM) P4, Virbac [M1] and mini VIDAS (R), bioMerieux [M2]) and a well-established radioimmunoassay (RIA), which was used as a reference method. Materials and Methods: Comparative measurements were performed on 52 blood serum samples collected from 45 clinically healthy bitches of different breeds. The dogs had been presented to determine the estrus cycle stage and predict the time of ovulation. Each sample was divided into three aliquots. In aliquot 1, P4 was measured immediately applying M2. Aliquots 2 and 3 were stored at -20 degrees C until analysis was performed using RIA and M1. The consistency of the three methods was investigated by pairwise linear regression analyses. Results: In RIA, the P4 concentrations ranged between 1.1 and 25.4 ng/mL. Regression analyses revealed highly significant (p<0.0001) positive correlations between the three methods applied (M1 vs. RIA: R=0.94; M2 vs. RIA: R=0.98; and MI vs. M2: R=.91). Conclusion: The results show that the two commercial on-site methods tested exhibit approximately equal, high consistency with the radioinununological reference method and can, therefore, be used beneficially in a clinical setting. However, biological interpretation of data must be performed in a method-specific manner.

Automated summary

This study compared the consistency of two commercial on-site methods and a radioimmunoassay in measuring blood progesterone concentration. The results showed that the two commercial on-site methods exhibited high consistency with the radioimmunoassay reference method and can be beneficially used in a clinical setting.