title: Condom use and vaginal Y-chromosome detection: the specificity of a potential biomarker.
abstract: OBJECTIVE
  Detection of vaginal Y-chromosome sequences (YCS) may be a useful biomarker to validate sexual behavior reporting in women. We describe the effects of condom use on the detection of vaginal YCS.
  
  
  METHODS
  Fifty-six women were asked to abstain from sexual intercourse for 14 days. On day 15, participants were asked to engage in sexual intercourse with their male partners using condoms. Self-collected vaginal swabs were obtained on days 14, 16, and 17. YCS were detected using the Roche LightCycler with the use of positive controls.
  
  
  RESULTS
  Fourty-four of 56 women completed the study. Five women (11.4%) had detectable YCS. The overall specificity of the YCS assay with condom use was 92% (95% CI: 80%-98%). Although women who reported receptive oral sex and digital penetration within 48 hours of swab collection had a higher detection rate of YCS [RR 2.3 (95% CI: 1.1-4.6) and 3.6 (95%CI: 1.6-8.5), respectively], the mean concentration of YCS was much less than that associated with unprotected vaginal intercourse (P <0.001)
  
  
  CONCLUSIONS
  Condom use during intercourse appears to prevent vaginal YCS detection; this may be a useful biomarker to validate self-reported condom use.
authors.affiliation: Division of Infectious Diseases, Bayview Medical Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Khalil G
authors.initials: KG
authors.lastname: Ghanem
authors.forename: Johan H
authors.initials: JH
authors.lastname: Melendez
authors.forename: Corlina
authors.initials: C
authors.lastname: McNeil-Solis
authors.forename: Julie A
authors.initials: JA
authors.lastname: Giles
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Yuenger
authors.forename: Tukisa D
authors.initials: TD
authors.lastname: Smith
authors.forename: Jonathan
authors.initials: J
authors.lastname: Zenilman
mesh_terms: D015415:Biomarkers / Q000032:analysis; D041322:Chromosomes, Human, Y / Q000737:chemistry*; D017280:Condoms; D004247:DNA / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D011237:Predictive Value of Tests; D012661:Semen / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012749:Sexually Transmitted Diseases / Q000517:prevention & control*; D014626:Vaginal Smears
chemical_list: D015415:Biomarkers; D004247:DNA