title: Comparison of a combined nontreponemal (VDRL) and treponemal immunoblot to traditional nontreponemal and treponemal assays.
abstract: BACKGROUND
  Serology is the mainstay for the diagnosis and management of patients with syphilis. Newer technologies such as immunoblotting are now available for the diagnosis of syphilis.
  
  
  METHODS
  A commercial IgM/IgG immunoblot assay that detects both nontreponemal (VDRL-Venereal Disease Research Laboratory) and treponemal antibodies was compared with standard nontreponemal and treponemal assays. The immunoblot and T. pallidum particle agglutination assay (TP-PA) were performed on 198 samples. Ninety-seven samples were Rapid plasma reagin (RPR)-positive and one hundred one were RPR-negative. Positive RPR samples were titered by VDRL.
  
  
  RESULTS
  The agreement, sensitivity, and specificity of the IgM/IgG VDRL results of the immunoblot compared to RPR were 74.2% (95% CI: 67.2-80.2), 77.3% (95% CI: 70.2-83.4), and 71.3% (95% CI: 64.4-77.1), respectively. The agreement, sensitivity, and specificity of the IgM/IgG treponemal immunoblot compared to TP-PA were 100% for all parameters, if the ten equivocal results were not used in the calculation.
  
  
  CONCLUSIONS
  The treponemal portion of the ViraBlot IgM/IgG immunoblot compared well with the treponemal confirmation assay and could be a useful supplemental method to fluorescent treponemal antibody or TP-PA for the confirmation of syphilis. The addition of the detection of nontreponemal antibodies to the immunoblot assay, however, may not be of added benefit to the overall assay, due to decreased sensitivity and specificity compared to standard assays.
authors.affiliation: Department of Pathology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia.
authors.forename: Alicia A
authors.initials: AA
authors.lastname: Franken
authors.forename: Joyce H
authors.initials: JH
authors.lastname: Oliver
authors.forename: Christine M
authors.initials: CM
authors.lastname: Litwin
mesh_terms: D000906:Antibodies / Q000097:blood*; D001431:Bacteriological Techniques / Q000379:methods*; D002308:Cardiolipins / Q000097:blood* / Q000276:immunology*; D016009:Chi-Square Distribution; D002784:Cholesterol / Q000097:blood* / Q000276:immunology*; D016001:Confidence Intervals; D006801:Humans; D015151:Immunoblotting / Q000379:methods*; D010713:Phosphatidylcholines / Q000097:blood* / Q000276:immunology*; D011933:Reagent Kits, Diagnostic; D013587:Syphilis / Q000175:diagnosis*; D014208:Treponema / Q000276:immunology
chemical_list: D000906:Antibodies; D002308:Cardiolipins; D010713:Phosphatidylcholines; D011933:Reagent Kits, Diagnostic; C054448:VDRL antigen; D002784:Cholesterol
keywords: RPR; immunoblot; nontreponemal; syphilis; treponemal