RPR (VDRL) is test for screening syphilis. RPR stands for Rapid Plasma Reagin and the abbreviation VDRL stands for Venereal Disease Research Laboratory which developed this test. The test ascertains if there are antibodies caused die to Syphilis, in the blood of affected person. Syphilis is caused due to infection by the bacterium Treponema pallidum. This test is also useful for confirming the presence of an active infection and also in monitoring the progress of treatment for syphilis. The quantitative measure of the level or titer of antibody measured is used to ascertain this.