Evaluation of mare endometrial cytology using the novel cytotape technique

Abstract

The cytobrush is considered the method of choice to obtain endometrial samples. Rigid brush fibers, however, may induce endometrial irritation and bleeding, or cell fragmentation, decreasing quality and diagnostic value of the samples. It was hypothesized that samples collected using a novel cytotape would provide sample smears of greater quality and less blood contamination than the cytobrush. Endometrial samples were collected with a cytotape and a cytobrush from ten mares without endometritis. Endometritis was then induced with artificial insemination, and samples were again collected 6 h after insemination. A cytology smear and bacterial culture were prepared from each sample. The collection methods and times were compared in terms of number and integrity of endometrial cells; number, integrity, and percentage of neutrophils; number of red blood cells, and number of colony-forming units. Frequency of positive cytology and culture was compared when there was use of each technique. The sensitivity, specificity, positive predictive value, and negative predictive value of cytology and culture for each technique was calculated using endometrial biopsy as the gold standard. While all samples had adequate and comparable cellularity and cell integrity, cytotape samples had less red blood cell contamination compared to cytobrush samples (P < 0.05). The number and percentage of PMNs, frequency of positive cytology diagnosis, number of colony-forming units and frequency of positive cultures did not differ between collection methods. In conclusion, the cytotape is a rapid, easy, and practical technique that can provide endometrial samples with similar diagnostic value to the cytobrush, but with less blood contamination.