Non-chlamydial non-gonococcal urethritis or undiagnosed chlamydial urethritis?

The aim of this study is to investigate the prevalence of sexually transmitted infections (STI) in the partners of men with non-chlamyclial, non-gonococcal urethritis (NCNGU). Observational study of the sexual partners of men with NCNGU diagnosed in the Department of Genitourinary Medicine, Edinburgh between 1 June 2002 and 31 December 2003. The diagnosis of chlamydial infection was based on ligase chain reaction (LCx) between June 2002 and March 2003, and on polymerase chain reaction (PCR) thereafter. Gonococcal infection was diagnosed with culture method. Sexual partners of 99 (25%) of the 403 heterosexual men diagnosed with NCNGU were screened. Chlamydial infection was detected in 19 (19%) of the female sexual partners. Higher proportion of female partners of symptomatic men (15/51) had chlamydial infection compared with that of partners of asymptomatic men (4/48) (P < 0.005). NCNGU may be related to false-negative results of chlamydial diagnostic tests. Screening and treatment of sexual partners of men with NCNGU is therefore necessary.