Comparison of the Cytology Brush and Low Volume Lavage Techniques to Evaluate Endometrial Cytology for Diagnosing Endometritis in Chronically Infertile Mares

Abstract

Endometritis is the most common cause of subfertility and infertility in mares that leads to great economical loss. Endometrial cytology (EC) is a reliable diagnostic tool, widely used to assess the health of the reproductive tract in both humans and domestic mammals. The aim of this study was to compare two techniques for the collection of EC samples in chronically infertile mares. Ten mares aged 4 to 20 were used. In each mare, samples for EC were collected first by cytology brush (CB) and then by low volume lavage (LVL) and stained using the Diff Quick stain. Each sample was assessed for the following parameters: background of the slides, quality and quantity of the cells obtained, number of inflammatory cells. Also, we assessed the number of operators, time and costs needed for each technique. More debris was noticed in the LVL samples, as well as a higher percentage of distorted cells. However, inflammatory cells were detected in all positive samples. Sampling by LVL required two to three operators and recovery of the lavage fluid was sometimes difficult. In conclusion, both techniques are accurate for the detection of uterine inflammation.

Use of cytobrush for bacteriological and cytological diagnosis of endometritis in mares

“…The CB specimens obtained in the field exhibited superior preservation of both quantity and quality of cells for cytological analysis compared to those obtained from the same brush after transport to the lab in a sterile saline solution. Low-volume flushes, CBs, and CSs have been validated for the cytological evaluation of the endometrium in mares [ 4 , 11 , 16 , 17 ]. Moreover, the use of a double-guarded CB has been demonstrated to improve diagnostic accuracy for endometrial cytology in mares and women [ 5 , 8 , 11 , 12 , 21 , 31 ].…”

“…Cytological slides prepared immediately after collection had more background, red blood cell contamination, and more intact endometrial and inflammatory cells than LS and PS. The presence of mucus and debris, including degenerated neutrophils, destroyed epithelial cells, and inflammatory residue, in the background of cytological samples may indicate a trace of inflammation and has been consistently associated with positive cultures [ 16 , 17 , 31 ]. The use of the novel cytotape technique demonstrated less blood contamination than the samples collected using a CB [ 14 ].…”

“…Using a double-guarded cotton swab (CS) to obtain samples from the surface of the endometrium for bacteriological culture is a standard practice. Even if different techniques, such as low-volume flush or endometrial biopsy, have proven to be useful in determining the presence of endometrial disease, they are less frequently used in the field due to their costs, complexity, and/or invasiveness [ 15 – 17 ]. Above all, in the field, diagnostic methods should be sensitive and specific but also simple, time-efficient, and cost-effective.…”