Rapid Plasma Reagin (RPR) is a blood test used to screen for syphilis, a sexually transmitted infection. It detects non-specific antibodies that the body produces in response to the infection. The test is quick and can provide results within a few hours, making it a convenient option for initial screening. If the RPR test is positive, further testing is usually required to confirm the diagnosis of syphilis. The RPR test is not specific to syphilis, so it may yield false-positive results due to other conditions. Therefore, it is important to follow up with more specific tests for accurate diagnosis.