From the Research
RPR (Rapid Plasma Reagin) is a blood test used to screen for syphilis infection, and if positive, follow-up testing with a more specific treponemal test like TP-PA or FTA-ABS is recommended to confirm the diagnosis. The RPR test detects antibodies to cardiolipin, which are produced during syphilis infection, but it can yield false positives in certain conditions like autoimmune diseases, pregnancy, or other infections 1. For patients with confirmed syphilis, treatment typically involves penicillin G benzathine, with the specific regimen depending on the stage of infection.
Treatment Regimens
- Early syphilis (primary, secondary, or early latent) is usually treated with a single intramuscular injection of 2.4 million units of penicillin G benzathine.
- Late latent syphilis or syphilis of unknown duration requires three weekly injections of 2.4 million units.
- For neurosyphilis, the recommended treatment is aqueous crystalline penicillin G 3-4 million units IV every 4 hours for 10-14 days.
Alternative Treatments
Patients allergic to penicillin may be treated with doxycycline 100mg orally twice daily for 14-28 days, depending on the stage 2. Follow-up RPR testing is essential to monitor treatment response, typically at 3,6, and 12 months. The performance of various syphilis serological tests, including RPR, has been evaluated in comparison with the FTA-abs test, showing that treponemal immunoassays generally perform well and may be an alternative for screening total antibodies in syphilis infection 1. Automated RPR and TPPA tests could be alternatives to conventional syphilis tests, with AutoRPR being particularly suitable for treatment monitoring 3.