title: Evaluation of self-collected vaginal swab, first void urine, and endocervical swab specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in adolescent females.
abstract: OBJECTIVE
  To assess the concordance of self-obtained vaginal swabs (SVS), first void urine samples (FVU) and provider-collected endocervical swabs (PES) for the detection of Chlamydia trachomatis (CT) and Neisseria gonorrhea (NG) in adolescents.
  
  
  METHODS
  A total of 342 adolescent women and 1080 baseline and semi-annual visits were analyzed. FVU, SVS and PES were collected at each biannual visit. All specimens were tested by BDProbeTec ET(trade mark) Amplified DNA Assay. Sensitivity, specificity, positive predictive value (PPV) negative predictive value (NPV) and kappa coefficient were calculated to evaluate the ability to identify possible infected cases using samples from three anatomic sites and the test agreement between any two of these three specimen types. Positive results from at least two of the three specimens collected from same subject at the same study visit was considered true positive.
  
  
  RESULTS
  The positivity rates for CT and NG were 26.6 and 11.7 per 100 women respectively. The sensitivities of SVS, FVU and PES for detecting CT were 97.3%, 89.2% and 90.1% respectively. For the detection of NG, the sensitivities of the three sampling methods were 100%, 88.6% and 95.5% respectively. The specificities were between 94.7% and 99.7% for both CT and NG. Kappa coefficients of CT test results were 0.89, 0.88 and 0.83 for specimen pairs SVSvsPES, SVSvsFVU and PESvsFVU respectively. For the detection of NG, kappa coefficients were 0.91, 0.87 and 0.91 for these three pairs (all P<0.0001). Kappa>0.75 is considered excellent agreement between specimens.
  
  
  CONCLUSIONS
  There were strong agreements among SVS, PES and FVU specimens on the detection of CT and NG infections in adolescent females using nucleic acid amplification test. SVS represented as high as or more sensitive an approach for detecting both CT and NG compared to PES. Although FVU was the least sensitive sampling method, it is also the least invasive method. Thus SVS and FVU may provide a reliable alternative to endocervical specimens for CT and NG screening.
authors.affiliation: Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. jfang@peds.umaryland.edu
authors.forename: Junyong
authors.initials: J
authors.lastname: Fang
authors.forename: Constance
authors.initials: C
authors.lastname: Husman
authors.forename: Lalitha
authors.initials: L
authors.lastname: DeSilva
authors.forename: Ruzhang
authors.initials: R
authors.lastname: Chang
authors.forename: Ligia
authors.initials: L
authors.lastname: Peralta
mesh_terms: D000293:Adolescent; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000382:microbiology / Q000652:urine; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis* / Q000382:microbiology / Q000652:urine; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012749:Sexually Transmitted Diseases / Q000175:diagnosis* / Q000382:microbiology / Q000652:urine; D014626:Vaginal Smears / Q000379:methods