Midstream Testing Effectively Diagnoses Chlamydia Trachomatis

Midstream urine testing effectively detects Chlamydia trachomatis, according to a study published in Annals of Family Medicine.

“These results suggest that when using newer NAAT techniques, timing of urine specimen collection is not as important in testing for C trachomatis as previously thought,” the authors wrote.

Dr. Derelie Mangin, associate professor and director of the general practice research group at the University of Otago, Christchurch, New Zealand, and colleagues conducted a prospective study of 100 women for whom a recent vaginal swab specimen tested positive for C trachomatis. Ages ranged from 17 years to 45 years with a median age of 20 years. Almost half (41%) of the women presented for a general sexual health check; the remainder had urinary tract symptoms, other symptoms, or had a partner who tested positive C trachomatis.

Mangin et al. designed the study to determine the sensitivity of the nucleic acid amplification tests (NAAT) on midstream specimens as compared with NAAT-positive first-void specimens. As such, the women provided both first-void and midstream urine samples. The researchers found that midstream testing was virtually as effective as first urine specimens; they noted that 96% of the midstream samples tested positive.

“The clinical practice implications of these results are important: urine culture and C trachomatis testing may be considered on a single specimen,” Mangin and colleagues explained. “In the clinical setting, using one sample avoids the practical difficulties of collecting (or being unable to collect) further specimens from patients with uncertain diagnosis after midstream urine testing for urinary tract infection. It may also be helpful where the women are at risk or report symptoms of both infections.”

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References:

Mangin D, Murdoch D, Wells JE, et al. Chlamydia trachomatis testing sensitivity in midstream compared with first-void urine specimens. Ann Fam Med. 2012;10(1):50-3.