The dependability of the Treponema pallidum immobilization (TPI) test in differentiating biologic false-positive reactions for syphilis from those due to infection with the other treponemes has been well established. The procedure is difficult and expensive because motile treponemes are essential as the antigen. Search for a simpler test led to the development of the T. pallidum immune adherence (TPIA) test by Nelson in 1953,1 which employs for an antigen killed T. pallidum. The test is based on the principle that T. pallidum sensitized by specific antibody in the patient's serum adheres to the surface of human red blood cells in the presence of complement. On the other hand, adherence of T. pallidum does not take place in the presence of normal serum and complement.
Materials and Methods
Comparative serologic studies were carried out with the T. pallidum immobilization and T. pallidum immune adherence tests on 189 serum samples. Of