Specific direct fluorescent antibody detection of Treponema pallidum.

In a study to determine the reliability of specific direct fluorescent antibody staining of Treponema pallidum (DFATP) in lesion exudate, and to evaluate it as a potential diagnostic test to be used in lieu of or as an adjunct to the darkfield and other laboratory tests as an aid in the diagnosis of early syphilis, two types of comparisons were made: Study A-Replicate specimens from each of 350 lesions were examined in the state laboratory by DFATP and in the field by darkfield microscopy and the results were compared; Study B--95 specimens of lesion exudate were tested by the DFATP test and compared with the Fluorescent Treponemal Antibody Absorption (FTA-ABS) test on patients' sera. The tests in each study were evaluated as to sensitivity, specificity, and agreement with each other. The DFATP proved to be as reliable as the darkfield, was advantageous in some instances, and can be valuable when a darkfield examination is not feasible. Much of the responsibility of an adequate DFATP or darkfield test rests on the one who takes the specimen.