title: Testing for amphetamine-type stimulant (ATS) use to ascertain validity of self-reported ATS use among young female sex workers in Cambodia.
abstract: OBJECTIVE
  To assess concordance between self-reported amphetamine-type stimulant (ATS) use and toxicology results among young female sex workers (FSW) in Phnom Penh, Cambodia.
  
  
  METHODS
  Cross-sectional data from the Young Women's Health Study-2 (YWHS-2), a prospective study of HIV and ATS use among young (15 to 29 years) FSW in Phnom Penh, Cambodia, was analyzed. The YWHS-2 assessed sociodemographic characteristics, HIV serology, HIV risk, and ATS use by self-report and urine toxicology testing at each quarterly visit, the second of which provided data for this assessment. Outcomes include sensitivity, specificity, positive- and negative predictive values (overall and stratified by age), sex-work setting, and HIV status.
  
  
  RESULTS
  Among 200 women, prevalence of positive toxicology screening for ATS use was 14% (95% confidence interval [CI], 9.2, 18.9%) and concurrent prevalence of self-reported ATS was 15.5% (95% CI, 10.4, 20.6%). The sensitivity and specificity of self-reported ATS use compared to positive toxicology test results was 89.3% (25/28), and 96.5% (166/172), respectively. The positive predictive value of self-reported ATS use was 80.6% (25/31); the negative predictive value was 98.2% (166/169). Some differences in concordance between self-report and urine toxicology results were noted in analyses stratified by age group and sex-work setting but not by HIV status.
  
  
  CONCLUSIONS
  Results indicate a high prevalence of ATS use among FSW in Phnom Penh, Cambodia, and high concordance between self-reported and toxicology-test confirmed ATS use.
authors.affiliation: School of Public Health, University of California at Berkeley, Berkeley, California, USA.
authors.forename: Vannda
authors.initials: V
authors.lastname: Kab
authors.forename: Jennifer
authors.initials: J
authors.lastname: Evans
authors.forename: Neth
authors.initials: N
authors.lastname: Sansothy
authors.forename: Ellen
authors.initials: E
authors.lastname: Stein
authors.forename: Marie
authors.initials: M
authors.lastname: Claude-Couture
authors.forename: Lisa
authors.initials: L
authors.lastname: Maher
authors.forename: Kimberly
authors.initials: K
authors.lastname: Page
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D019969:Amphetamine-Related Disorders / Q000453:epidemiology* / Q000652:urine; D002160:Cambodia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006679:HIV Seropositivity / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D015995:Prevalence; D057566:Self Report; D012680:Sensitivity and Specificity; D060386:Sex Workers; D012959:Socioeconomic Factors; D055815:Young Adult