Sensitivity, Specificity and Predictive Values of Cytological and Microbiological Findings of Endometrial Biopsy, Cytobrush and Low Volume Uterine Lavage in Relation to Endometrial Histology in Barren Mares

Abstract

This study was carried out on 10 infertile barren mares to evaluate the sensitivity, specificity, predictive values and agreement (kappa
value) of cytological and microbiological findings of three diagnosing techniques of endometritis, viz., endometrial biopsy (EB), cytobrush
(CB) and low volume uterine lavage (LVL) in relation to endometrial histology. When histological examinations from EB were used as “the
best standard,” the sensitivity of cytology from EB, CB and LVL technique was 0.33, 0.50 and 0.50; specificity 0.75, 1.00 and 0.75; positive
predictive value 0.66, 1.00 and 0.75, and negative predictive value was 0.42, 0.57 and 0.50, respectively. The sensitivity of bacteriology
from EB, CB and LVL technique was 0.83, 0.83 and 1.00; the specificity was 0.75, 0.75 and 0.50; positive predictive value 0.83, 0.83 and
0.75, and the negative predictive value was 0.75, 0.75 and 1.00, respectively. In all the cases, the sensitivity of the bacteriology was found
to be higher than the sensitivity of cytology. When the results of cytological and bacteriological examinations were combined, no any
increase in the sensitivity was found. Bacteriology and cytology from CB showed the highest positive predictive value demonstrating
that a positive result is an accurate indication of endometritis. Sensitivity values were always higher if smears were evaluated according to
PMNs to epithelial cell ratio, and the highest values were observed in specimens collected from CB and LVL. The evaluation of cytological
smears based on counting PMNs in relation to epithelial cells was a better method for diagnosis of endometritis than counting the
number of PMNs per high power microscopic field (k value 0.07-0.47 vs. 0.00). The agreement of the diagnosis of endometritis between
the three techniques of the collection was from fair to poor and between the different criteria adopted to evaluate smears was always
poor. However, the agreement of the diagnosis of endometritis by the microbial culture was moderate between the three techniques
of the collection (k value 0.55-0.58).