An RPR test, or rapid plasma reagin test, is a blood test that is used to screen for syphilis. It is a non-treponemal test, which means that it does not directly detect the bacteria that causes syphilis (Treponema pallidum). Instead, it detects antibodies that the body produces in response to the bacteria.
The RPR test is a simple and inexpensive test that can be done quickly. It is often used as a screening test for syphilis, especially in people who are at high risk for the infection, such as people who have multiple sexual partners or who have a history of sexually transmitted infections.
A positive RPR test means that the person has antibodies to syphilis. However, a positive test does not necessarily mean that the person has active syphilis. The infection may be latent (dormant) or the person may have been treated for syphilis in the past.
A negative RPR test means that the person does not have antibodies to syphilis. However, a negative test does not rule out the possibility of syphilis, especially if the person has been recently infected.
The RPR test is usually followed up with a treponemal test, such as the fluorescent treponemal antibody absorption (FTA-ABS) test, to confirm the diagnosis of syphilis.
The normal range for the RPR test is 0-0.001 units. A titer of 0.010 or higher is considered positive. The titer (or level) of the RPR test can be used to track the progress of the infection and to monitor the response to treatment.
The RPR test is a safe and reliable test. However, there are some false positive results, which means that the test may be positive even though the person does not have syphilis. False positive results can occur in people who have other infections, such as Lyme disease or lupus.
If you have a positive RPR test, you should see your doctor for further testing and treatment. Syphilis is a treatable infection, but it can be serious if it is not treated.