Cervical wet mount as a negative predictor for gonococci- and Chlamydia trachomatis-induced cervicitis in a gravid population

OBJECTIVE: The purpose of this study was to determine whether a wet mount preparation of endocervical secretions from obstetric patients can accurately rule out the presence of gonococci and Chlamydia trachomatis. STUDY DESIGN: Gravid patients were screened for gonococci and C trachomatis with a deoxyribonucleic acid probe and a wet mount preparation of endocervical secretions. The number of polymorphonuclear lymphocytes was counted and averaged per x400 high-power field. A count of <10 polymorphonuclear lymphocytes per high-power field was defined as predicting the absence of gonococci- and C trachomatis-induced cervicitis. A chi(2) analysis was used to compare the wet mount results to the deoxyribonucleic acid probe. RESULTS: Between January and March 1998, 341 patients were enrolled in the study. Wet mount results showed 32% (108/341) of patients had <10 polymorphonuclear lymphocytes per high-power field. The incidence of infection with gonococci and C trachomatis in this population, as determined by deoxyribonucleic acid probe, was 10 of 341 (2.9%) and 30 of 340 (8.8%), respectively. The sensitivity values for gonococci and C trachomatis were 90% and 87%, respectively. The negative predictive value of the wet mount for gonococci-induced cervicitis was 99%, and that for C trachomatis-induced cervicitis was 96%. CONCLUSION: In this population the wet mount accurately predicted the absence of gonococci- and C trachomatis-induced cervicitis. Use of this screening protocol in gravid patients has the potential to reduce the cost of screening for these 2 diseases.