Treponema Pallidum Western Blot: Comparison With the FTA-ABS Test as a Confirmatory Test for Syphilis

Diagn Microbiol Infect Dis. 2001 Jan;39(1):9-14. doi: 10.1016/s0732-8893(00)00213-3.


We developed a Treponema pallidum Western blot and compared the results with Treponema pallidum particle agglutination (TPPA) and fluorescent treponemal antibody absorption (FTA-ABS) tests. The Western blot was deemed reactive if the serum reacted with at least three major antigenic bands (TpN47, TpN44.5, TpN17, TpN15). The sensitivities of the Western blot, TPPA and FTA-ABS, were all 100% and the specificities of the Western blot, TPPA and FTA-ABS were 100%, 100% and 94.5% respectively. In 52 problem sera, reactive in only one treponemal test, the agreement between the Western blot and TPPA (61.5%) was significantly better than between Western blot and FTA-ABS (38.5%). The individual sensitivities and specificities of TpN47, TpN44.5, TpN17, TpN15 were 100%, 100%, 96%, 100% and 20%, 96%, 100%, 100% respectively. We conclude that the Western blot is a useful additional confirmatory test or alternative to the FTA-ABS and that a more sensitive and specific criterion for the Western blot would be reactivity with TpN15 and two of the three other major antigens.

Publication types

  • Comparative Study

MeSH terms

  • Agglutination Tests / methods
  • Antibodies, Bacterial / blood
  • Antigens, Bacterial / blood
  • Antigens, Bacterial / immunology
  • Blotting, Western / methods*
  • Fluorescent Treponemal Antibody-Absorption Test / methods
  • Immunoglobulin G / blood
  • Immunoglobulin M / blood
  • Sensitivity and Specificity
  • Syphilis / diagnosis*
  • Syphilis Serodiagnosis
  • Treponema pallidum / immunology*
  • Treponemal Infections / diagnosis


  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Immunoglobulin G
  • Immunoglobulin M