title: Utility of the Determine Syphilis TP rapid test in commercial sex venues in Peru.
abstract: OBJECTIVE
  This study sought to evaluate the utility of the Determine Syphilis TP test performed in Peruvian commercial sex venues for the detection of active syphilis; and determine the feasibility of integrating rapid syphilis testing for female sex workers (FSW) into existing health outreach services.
  
  
  METHODS
  We tested 3586 female sex workers for syphilis by Determine in the field using whole blood fingerstick, and by rapid plasma reagin (RPR) and Treponema pallidum haemagglutination assay (TPHA) in a central laboratory in Lima using sera.
  
  
  RESULTS
  97.4% of the FSW offered rapid syphilis testing participated; and among those who tested positive, 87% visited the local health centre for treatment. More than twice as many specimens were RPR reactive using serum in Lima (5.7%) than tested positive by whole blood Determine in the field (2.8%), and although most were confirmed by TPHA, only a small proportion (0.7%) were RPR reactive at >or=1:8 dilutions, and likely indicating active syphilis. Sensitivity, specificity and positive predictive value of the Determine Syphilis TP test in whole blood when compared to serum RPR reactivity at any dilution confirmed by TPHA as the gold standard were 39.3%, 99.2% and 71.4%, respectively. Sensitivity improved to 64.0% when using serum RPR >or=1:8 confirmed by TPHA. Invalid tests were rare (0.3%).
  
  
  CONCLUSIONS
  Rapid syphilis testing in sex work venues proved feasible, but Determine using whole blood obtained by fingerstick was substantially less sensitive than reported in previous laboratory-based studies using serum. Although easy to perform in outreach venues, the utility of this rapid syphilis test was relatively low in settings where a large proportion of the targeted population has been previously tested and treated.
authors.affiliation: Unidad de Epidemiología, Enfermedades de Transmisión Sexual y SIDA, Facultad de Salud Pública y Administración, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: P E
authors.initials: PE
authors.lastname: Campos
authors.forename: A L
authors.initials: AL
authors.lastname: Buffardi
authors.forename: M
authors.initials: M
authors.lastname: Chiappe
authors.forename: C
authors.initials: C
authors.lastname: Buendía
authors.forename: P J
authors.initials: PJ
authors.lastname: Garcia
authors.forename: C P
authors.initials: CP
authors.lastname: Carcamo
authors.forename: G
authors.initials: G
authors.lastname: Garnett
authors.forename: P
authors.initials: P
authors.lastname: White
authors.forename: K K
authors.initials: KK
authors.lastname: Holmes
mesh_terms: D005240:Feasibility Studies; D005260:Female; D006385:Hemagglutination Inhibition Tests / Q000379:methods / Q000592:standards; D006801:Humans; D010568:Peru; D019095:Point-of-Care Systems / Q000592:standards; D012680:Sensitivity and Specificity; D011477:Sex Work; D013587:Syphilis / Q000175:diagnosis*; D013588:Syphilis Serodiagnosis / Q000379:methods* / Q000592:standards; D014210:Treponema pallidum / Q000302:isolation & purification