Abstract: Objectives To study the incidence of Trichomonas vaginalis(TV)infection in Chinese male patients with nongonococcal urethritis(NGU),to evaluate the sensitivity and specificity of urine-based and urethral swab polymerase chain reaction(PCR)detection,and to set up a method of non-invasive detection for male TV infection.Methods One hundred and five male NGU patients were collected from the STD clinic.Two urethral swabs were obtained from each patient,one for InPouch TV culture system,the other for PCR;one urine specimen(first-void urine or first-catch urine)was also collected for PCR detection.Culture was considered as the"gold standard".Compared with the culture,the sensitivity,specificity,positive predictive value(PPV)and negative predictive value(NPV)of two PCR detection were calculated.Results The positive rate of InPouch TV system detection was4.76%(5/105);the positive rate of urine-based PCR and urethral swab PCR detection was 3.81%(4/105)and 4.76%(5/105),respectively.In comparison with the culture,the sensitivity,specificity,PPV and NPV were 80%,100%,100% and 99% for urine-based PCR and 80%,99%,80% and 99% for urethral swab PCR.Conclusions TV is one of the etiological agent for male NGU,the positive rate of TV is 4.76% in our study.The urine-based PCR detection has a higher sensitivity and specificity and provides a noninvasive method which is feasible in practice.

Key words: Urethritis, Trichomonas vaginalis, Cells,cultured, Polymerase chain reaction