title: Confirmation of high specificity of an automated enzyme immunoassay test for serological diagnosis of syphilis: retrospective evaluation versus results after implementation.
abstract: BACKGROUND
  The optimal algorithm for serological syphilis screening is still a matter of debate. We have previously evaluated the performance of the Bioelisa Syphilis 3.0, using a selection of archived sera, and in this study compare these results with the Bioelisa results after clinical implementation.
  
  
  METHODS
  All Bioelisa Syphilis 3.0 results obtained since clinical implementation were analyzed. Bioelisa-positive or borderline samples were retested using Treponema pallidum particle agglutination, rapid plasma reagin test, fluorescent treponemal antibody-absorption test, and/or immunoblot. On sera sent in together with cerebrospinal fluid, occasionally both the T. pallidum particle agglutination and Bioelisa were performed.
  
  
  RESULTS
  The Bioelisa was performed on 14,622 sera. Bioelisa-positive samples, which were not retested by the previously described assays, were withdrawn from the database (n = 36). In 1.3% of the samples (187/14,586), the Bioelisa was positive or borderline and, ultimately, 115 sera were considered true positive (prevalence 0.8%). The specificity of the Bioelisa was 99.5%.
  
  
  CONCLUSIONS
  Based on the results of all performed diagnostic assays, the specificity of the Bioelisa of 99.5% is very consistent with that found in the initial study (100%; 95% confidence interval was 98.0%-100%). Interpreting (positive) test results is difficult in the absence of a gold standard, especially when the disease prevalence is low. Results should be viewed in the light of the patients' characteristics.
authors: From the *Department of Medical Microbiology, CAPHRI School of Public Health and Primary Care, Maastricht University Medical Centre, AZ, Maastricht, the Netherlands; †Department of Sexual Health, Infectious Diseases and Environmental Health, Public Health Service South Limburg, HA, Geleen, the Netherlands; and ‡Department of Epidemiology, CAPHRI School of Public Health and Primary Care, Maastricht University Medical Centre, AZ, Maastricht, the Netherlands.
authors: Laura
authors: L
authors: van Dommelen
authors: Christian J P A
authors: CJ
authors: Hoebe
authors: Frank H
authors: FH
authors: van Tiel
authors: Carel
authors: C
authors: Thijs
authors: Valère J
authors: VJ
authors: Goossens
authors: Cathrien A
authors: CA
authors: Bruggeman
authors: Inge H M
authors: IH
authors: van Loo
mesh_terms: D000907:Antibodies, Bacterial / Q000302:isolation & purification*; D016508:Fluorescent Treponemal Antibody-Absorption Test / Q000379:methods*; D006801:Humans; D011933:Reagent Kits, Diagnostic; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013587:Syphilis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D014210:Treponema pallidum / Q000302:isolation & purification*
chemical_list: D000907:Antibodies, Bacterial; D011933:Reagent Kits, Diagnostic