Percoll-purified Treponema pallidum, an improved fluorescent treponemal antibody-absorbed antigen.

Percoll-purified Treponema pallidum was evaluated as a fluorescent treponemal antibody-absorbed antigen. Borderline and false-positive reactions were essentially eliminated, resulting in sensitivity and specificity of 100 and 95.5%, respectively. The lack of background debris improved the ease and speed of reading the test.