An immunofluorescence method for the diagnosis of primary syphilis using an absorption technique.

An immunofluorescence technique for demonstrating Treponema pallidum in fixed films made from suspected chancre exudate is described. The method used is basically a reversal of the fluorescent treponemal antibody absorption test. It makes use of the fact that by using a syphilitic serum from which group antibody has been absorbed by an extract of Reiter treponemes, leaving only specific antibody, Treponema pallidum can be indentified. Neither the non-pathogenic genital treponemes nor mouth treponemes showed any fluorescence when tested by the technique described. All the reagents used in the test are available commercially, thus placing it within the scope of any laboratory with suitable fluorescence equipment. In the present state of knowledge of the treponematoses, this technique would seen to be the most accurate means of diagnosing primary syphilis because it permits the specific identification of Treponema pallidum in chancre exudate. It has the advantage over the dark-ground method that fixed films can be sent to the laboratory.