AND

A Treponemal test.

Diagnosis of syphilis can start either with a non-treponemal or a treponemal test. When the first test is a non-treponemal one, confirmation with a treponemal test is always required due to the multiple medical conditions that could result in a falsepositive nontreponemal test; some of these are HIV, autoimmune conditions, vaccines, injecting drug use, pregnancy, and older age. Nontreponemal test antibody titers are useful for monitoring treatment response.

If diagnosis of syphilis is established starting with a treponemal test, a quantitative non-treponemal test will be needed for patient management decisions. If nontreponemal test is negative, then the treponemal assay needs to be repeated, this should be different from the one used for initial testing.

Flow of non-treponemal and treponemal tests for decision-making is presented in **Figure 1**.
