EVALUATION OF A SCREENING ALGORITHM FOR THE DIAGNOSIS OF GENITAL INFECTIONS WITH NEISSERIA-GONORRHOEAE AND CHLAMYDIA-TRACHOMATIS AMONG FEMALE SEX WORKERS IN BENIN

Background and Objectives: In developing countries, simple and cheap p rocedures for the diagnosis of sexually transmitted diseases (STDs) ar e urgently needed, especially for screening purposes in high risk grou ps. Goals: To evaluate the sensitivity and specificity of a screening algorithm for STDs among 364 female sex workers in Benin, in compariso n with reference laboratory tests. Study Design: The algorithm relied on the following criteria, which were evaluated in sequence: the prese nce of endocervical mucopus on visual inspection of the cervix, a posi tive swab test, or a microscopic examination of vaginal fluid showing more than 10 polymorphonuclear cells per field. The algorithm diagnose d an infection if any one of these criteria was fulfilled. True infect ious status was determined by the combined results of culture for Neis seria gonorrhoeae, enzyme immunoassay for Chlamydia trachomatis, and p olymerase chain reaction assays for both infections. Results: Gonococc al or chlamydial infection was diagnosed in 39.8% of the study populat ion according to the reference tests, The algorithm had a sensitivity of 57.9% and a specificity of 61.2%. In the presence of Candida sp or Trichomonas vaginalis, specificity decreased to 39.1%, but sensitivity increased to 67.5%. Conclusions: These results underscore the limitat ions of simple, nonlaboratory diagnostic tools for screening STDs in h ighrisk groups in developing countries, Further research is needed to increase the validity-especially the sensitivity-of these algorithms.