title: Comparisons of fully automated syphilis tests with conventional VDRL and FTA-ABS tests.
abstract: BACKGROUND
  Serologic tests are widely used for the diagnosis of syphilis. However, conventional methods require well-trained technicians to produce reliable results. We compared automated nontreponemal and treponemal tests with conventional methods.
  
  
  METHODS
  The HiSens Auto Rapid Plasma Reagin (AutoRPR) and Treponema Pallidum particle agglutination (AutoTPPA) tests, which utilize latex turbidimetric immunoassay, were assessed. A total of 504 sera were assayed by AutoRPR, AutoTPPA, conventional VDRL and FTA-ABS. Among them, 250 samples were also tested by conventional TPPA.
  
  
  RESULTS
  The concordance rate between the results of VDRL and AutoRPR was 67.5%, and 164 discrepant cases were all VDRL reactive but AutoRPR negative. In the 164 cases, 133 showed FTA-ABS reactivity. Medical records of 106 among the 133 cases were reviewed, and 82 among 106 specimens were found to be collected from patients already treated for syphilis. The concordance rate between the results of AutoTPPA and FTA-ABS was 97.8%. The results of conventional TPPA and AutoTPPA for 250 samples were concordant in 241 cases (96.4%). AutoRPR showed higher specificity than that of VDRL, while VDRL demonstrated higher sensitivity than that of AutoRPR regardless of whether the patients had been already treated for syphilis or not. Both FTA-ABS and AutoTPPA showed high sensitivities and specificities greater than 98.0%.
  
  
  CONCLUSIONS
  Automated RPR and TPPA tests could be alternatives to conventional syphilis tests, and AutoRPR would be particularly suitable in treatment monitoring, since results by AutoRPR in cases after treatment became negative more rapidly than by VDRL.
authors: Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors: Seung Jun
authors: SJ
authors: Choi
authors: Yongjung
authors: Y
authors: Park
authors: Eun Young
authors: EY
authors: Lee
authors: Sinyoung
authors: S
authors: Kim
authors: Hyon-Suk
authors: HS
authors: Kim
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D057205:Automation, Laboratory; D016508:Fluorescent Treponemal Antibody-Absorption Test; D006801:Humans; D012680:Sensitivity and Specificity; D013587:Syphilis / Q000175:diagnosis* / Q000276:immunology; D014210:Treponema pallidum / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial