Interpreting serologic tests for syphilis.

Since syphilis is most often diagnosed by serologic studies, the correct interpretation of these tests is critical. Serologic tests are classified as nontreponemal of treponemal, according to the antigen employed. Flocculation tests are generally used for routine screening because of their simplicity. The treponemal procedures are more specific, but false-positive results may still occur. Results vary with the procedure, stage of disease and treatment. Significant difficulties remain with the serologic diagnosis of neurosyphilis and congenital syphilis.