RPR is a non-treponemal antibody test, meaning it detects antibodies against substances released by cells damaged by Treponema pallidum, the bacterium that causes syphilis, rather than antibodies to the bacterium itself. Positive results are typically confirmed with a treponemal-specific test.
This test is used to screen sexually active individuals, pregnant women (where syphilis screening is routine), patients with symptoms suggestive of syphilis, individuals being treated for other sexually transmitted infections, and as follow-up to monitor treatment response. Titer levels typically fall after successful treatment. Sample type is serum.