Background Urethritis is inflammation of the urethra, the main symptoms of which are dysuria and discharge, and two of the most common causes of which are Chlamydia trachomatis and Neisseria gonorrhoeae. The objectives of this study were to: (1) Determine the prevalence of atypical urethritis among participants, (2) Assess the sensitivity and specificity of using gram stain to diagnose gonorrhoea, and (3) Evaluate the effect of diagnostic test used on the time to treatment.

Methods A random sample of 600 eighteen to 60-year-old men who visited the SE STD Clinic from January 2008 to December 2009 and had a gram stain and nucleic acid amplification test (NAAT) performed were studied. Atypical urethritis was defined as having evidence of inflammation on gram stain but no evidence of gonorrhoea (ie, NGU) and a NAAT negative for both bacteria. The sensitivity and specificity of gram stain were calculated using NAAT as the gold standard. An analysis of variance was used to assess the relationship between time to treatment and diagnostic test—F statistics and corresponding p values were calculated. All statistical analyses were performed using SAS software V. 9 (SAS Institute Inc.) and WinPepi (Abramson, J.H. Epidemiologic Perspective and Innovations).

Results Of the 600 cases, 493 (82.3%) were Black, 253 (42.2%) had clinical urethritis, and 204 (47.0%) had a previous STD history. The mean age was 30.6 years (SD=10.3). One hundred and five cases of gonorrhoea, 110 cases of chlamydia, and three co-infections were diagnosed (Abstract P3-S1.36 table 1). None of the men diagnosed with gonorrhoea via gram stain were co-infected with chlamydia. The prevalence of atypical urethritis among this study population was 31.2%. The sensitivity of gram stain was 84.3%, the specificity was 100%, the positive predictive value (PPV) was 100%, and the negative predictive value (NPV) was 96.7%. The mean time to treatment was 2.52 days (SD=2.17). Analysis of variance revealed that gram stain (F=41.50, p<0.0001) and NAAT (F=19.18, p<0.0001) had significantly different effects on time to treatment.

Conclusion Gram stain is a reliable and relatively inexpensive test for the diagnosis of gonorrhoea among men. Men diagnosed with gonorrhoea or NGU using this point-of-care test were treated earlier than those diagnosed with NAAT only. The prevalence of atypical urethritis among this study population was high and further research should be conducted to investigate the possible aetiologies.