reagin ) and VDRL (Venereal Disease Research Laboratory test). If this comes back positive, or "reactive", then a confirmatory test must be done. (A negative test will most likely read as "non-reactive".)
Confirmation tests could be either an FTA-ABS (Fluorescent treponemal antibody-absorption) test, TPHA and MHA-TP (Treponema pallidum hemagglutination assays), TP-PA (Treponema pallidum particle agglutination assay). There are others, but those are the most common.
If you have a chancre (sore), they can culture it, but that isn't done as frequently as it used to be.