Specimens with positive Syphilis Total results are automatically tested for RPR titer and a confirmatory treponemal test (Treponema pallidum partical agglutination test).
For patients diagnosed with syphilis (i.e., positive Total and confirmatory test), the CDC recommends that response to therapy be assessed by RPR test (a 4-fold decline in titer, or undetectable RPR titer) after 6 months.
VDRL test is performed on CSF samples as a Sendout test for patients with positive serum test results, only.