Chlamydia trachomatis testing sensitivity in midstream compared with first-void urine specimens

Traditionally first-void urine specimens are used to test for Chlamydia trachomatis. In contrast, midstream urine specimens are traditionally recommended for microscopy and culture of presumptive bacterial urinary tract infections. The ability to test for both C trachomatis and urinary tract infection on a single midstream urine specimen would greatly aid clinical practice, as an urinary tract infection is an extremely common complaint in primary care. This study set out to determine how well positive C trachomatis results obtained on first-void specimens would correlate with positive findings in matched midstream specimens.

One hundred women with a first-void urine specimen positive for C trachomatis also provided midstream specimens for comparison. All specimens had C trachomatis testing performed using a DNA detection method.

Of the 100 eligible participants with a first-void specimen positive for C trachomatis, 96 (96%) also had a positive midstream specimen (95% exact confidence limits, 90.1%, 98.9%).

These results suggest that by using newer nucleic acid amplification techniques (NAATs), timing of specimen collection is not so important in testing for C trachomatis as previously thought. The sensitivity of NAAT testing on midstream urine specimens in women is sufficiently equivalent to testing on first-void specimens to consider in clinical practice and research settings where first-void specimens have formerly been collected.