title: Vulvovaginal-swab or first-catch urine specimen to detect Chlamydia trachomatis in women in a community setting?
abstract: Screening for chlamydia in women is widely recommended. We evaluated the performance of two nucleic acid amplification tests for detecting Chlamydia trachomatis in self-collected vulvovaginal-swab and first-catch urine specimens from women in a community setting and a strategy for optimizing the sensitivity of an amplified enzyme immunoassay on vulvovaginal-swab specimens. We tested 2,745 paired vulvovaginal-swab and urine specimens by PCR (Roche Cobas) or strand displacement amplification (SDA; Becton Dickinson). There were 146 women infected with chlamydia. The assays detected 97.3% (95% confidence interval [CI], 93.1 to 99.2%) of infected patients with vulvovaginal-swab specimens and 91.8% (86.1 to 95.7%) with urine specimens. We tested 2,749 vulvovaginal-swab specimens with both a nucleic acid amplification test and a polymer conjugate-enhanced enzyme immunoassay with negative-gray-zone testing. The relative sensitivities obtained after retesting specimens in the negative gray zone were 74.3% (95% CI, 62.8 to 83.8%) with PCR and 58.3% (95% CI, 46.1 to 69.8%) with SDA. In community settings, both vulvovaginal-swab and first-catch urine specimens from women are suitable substrates for nucleic acid amplification tests, but enzyme immunoassays, even after negative-gray-zone testing, should not be used in screening programs.
authors.affiliation: Public Health Laboratory Service, Birmingham Laboratory, Birmingham, UK.
authors.forename: Sue
authors.initials: S
authors.lastname: Skidmore
authors.forename: Paddy
authors.initials: P
authors.lastname: Horner
authors.forename: Alan
authors.initials: A
authors.lastname: Herring
authors.forename: Joanne
authors.initials: J
authors.lastname: Sell
authors.forename: Ian
authors.initials: I
authors.lastname: Paul
authors.forename: Jane
authors.initials: J
authors.lastname: Thomas
authors.forename: E Owen
authors.initials: EO
authors.lastname: Caul
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
authors.forename: Anne
authors.initials: A
authors.lastname: McCarthy
authors.forename: Emma
authors.initials: E
authors.lastname: Sanford
authors.forename: Chris
authors.initials: C
authors.lastname: Salisbury
authors.forename: John
authors.initials: J
authors.lastname: Macleod
authors.forename: Jonathan A C
authors.initials: JA
authors.lastname: Sterne
authors.forename: Nicola
authors.initials: N
authors.lastname: Low
mesh_terms: D000293:Adolescent; D000328:Adult; D001431:Bacteriological Techniques; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D021141:Nucleic Acid Amplification Techniques; D012680:Sensitivity and Specificity; D014556:Urine / Q000382:microbiology*; D014621:Vagina / Q000382:microbiology*; D014844:Vulva / Q000382:microbiology*