There are two types of diagnostic tests for syphilis - nontreponemal and treponemal tests. Both are required for an accurate diagnosis.
Nontreponemal tests are a useful screening option, but are not specific for syphilis, and can produce false-positive results. Any reactive samples in a nontreponemal test must also be analyzed with a treponemal test to confirm a syphilis diagnosis.
Treponemal tests detect antibodies that are specific to syphilis, but these antibodies usually remain detectable for life even after successful treatment; hence these tests identify both current and past, resolved infections.
The traditional ‘classic’ testing approach requires a nontreponemal test followed by a treponemal test. However, advances in testing techniques now mean that the ‘reverse screening’ approach (treponemal then nontreponemal) is more commonly used. DNA Testing Center of America offers a treponemal assay. Additional testing with a nontreponemal assay (not offered by DNA Testing Center of America) should be conducted on all samples that are reactive in this treponemal assay.