Testing Midstream Urine for Chlamydia trachomatis

First-void urine samples are recommended for diagnosing chlamydia with nucleic acid amplification tests, whereas midstream specimens are used for sediment evaluation and bacterial culture. Might midstream samples be sufficient for both purposes? In a New Zealand study, women with known chlamydial infections (based on positive vaginal swabs) collected concomitant first-catch and midstream urine samples; researchers then calculated the sensitivity of midstream urine specimen testing for detection of Chlamydia trachomatis.

Of 100 women with positive first-void urine specimens, 96 also had positive midstream specimens. However, 8 women had been excluded because they had positive vaginal swabs and negative (7) or inconclusive (1) first-void urine…