The Rapid Plasma Reagin test is a non-treponemal, macroscopic, flocculation-charcoal card agglutination test developed in the 1950s and 60s to screen for syphilis.
It acts as a faster, more accessible improvement on the VDRL (Venereal Disease Research Laboratory) test by detecting reaginic antibodies—which arise from tissue damage caused by T. pallidum—using cardiolipin antigen, charcoal particles, and choline chloride.













