Diagnosis of Trichomoniasis by detection of Antigens in Vaginal Discharge.

1Magda E Azab, 2Mohamed F Fikry, 1Mohamed H Abdel Baki, 1Fayza S Habib, 1Khalifa E Khalifa and 1Hala SI El-Wakil.

Departments of 1Parasitology and 2Gynaecology & Obstetric, Faculty Of Medicine, Ain Shams University, Cairo, Egypt.

The validity of an enyzme immunoassay test (ELISA EXO) to detect Trichomonas vaginalis exo-antigens in vaginal washout specimens of women complaining of vaginal discharge was investigated. The sensitivity, specificity, positive and negative predictive values of this test was compared with an enzyme immunoassay test (ELISA SO) for detection of somatic antigens as well as with double immunodiffusion technique for detection of Trichomonas exo and somatic antigens in vaginal washout specimens of 78 women. These cases were selected out of 300 patients attending the Early Cancer Detection Unit, Gynaecology Department, Ain shams University Hospitals, complaining of vaginal discharge with or without vulvovaginitis and primarily screened for trichomoniasis by wet mount and culture techniques. The results showed that ELISA test using either anti-somatic (HIS SO) or anti-exo-antigens (HIS EXO) hyperimmune sera gave 100 % sensitivities and negative predictive values. ELISA EXO gave higher specificity and positive predictive value (100 % for both) as compared with 92.5 % and 90.6 %, respective values for ELISA SO. Both ELISA tests gave higher sensitivities and negative predictive values than double gel immunodiffusion using HIS EXO and HIS SO which gave 31 % and 6.8 % sensitivities and 66.6 % and 57.9 % negative values, respectively. However, double gel immunodiffusion using both sera gave higher specificity and positive predictive values (100 %) than ELISA SO.