RPR (Rapid Plasma Reagin) Syphilis Blood Test

What is the purpose of this test?

The RPR (Rapid Plasma Reagin) Syphilis Blood Test is used to detect non-specific antibodies produced by the body in response to a syphilis infection caused by the bacterium Treponema pallidum. However, this test is not intended for initial screening or diagnosis of syphilis. Instead, it is typically used to monitor treatment response in individuals who have already been diagnosed with syphilis.

To screen for syphilis infection, current guidelines recommend using a reflex cascade that includes both a non-treponemal test like RPR and a treponema-specific assay. Appropriate screening options include:

• Treponema Pallidum (Syphilis) Screening Cascade Blood Test
• RPR (Diagnosis) with Reflex to Titer and Confirmatory Testing

When the RPR test is used to monitor treatment, a reflex titer test may be performed if the result is positive. This follow-up test measures the concentration of antibodies in the blood and can help evaluate the effectiveness of treatment or determine if the infection is still active.

It’s important to note that a positive RPR test does not confirm a syphilis diagnosis on its own, as other medical conditions—such as autoimmune diseases or certain infections—can also lead to false positives. Additional testing and clinical evaluation are necessary to confirm an active infection.

When should I order an RPR Syphilis Blood Test?

This test may be appropriate if you have already been diagnosed with syphilis and your healthcare provider wants to track your response to treatment. It is not recommended for individuals seeking an initial syphilis screening.

If you are experiencing any of the following symptoms or believe you may have been exposed to syphilis, please speak with your healthcare provider about ordering one of the recommended syphilis screening tests:

• Painful sores or ulcers on or around the genitals, anus, or mouth
• Rash (often on the palms of the hands or soles of the feet)
• Swollen lymph nodes
• Fever
• Fatigue
• Headache
• Sore throat