What are the different types of syphilis tests?

We use 2 different tests for syphilis, an EIA (enzyme immunoassays) test and a RPR (rapid plasma reagin) test.

When you ordered your STI tests, we asked if you’ve had a syphilis infection before. We use this information to work out which one of the tests you need.

If you do not know if you’ve had syphilis or not, that’s OK. We can still help you get tested and advise you on what to do next.

An EIA (enzyme immunoassays) syphilis test is what we give to people who tell us they have not had syphilis before. This looks for treponemal antibodies. These antibodies are created by your body when you get syphilis or a related infection. Once created, they stay in your body, even if the syphilis has been treated.

This test tells us if there are signs that you have had syphilis (or a related infection) in your body. This could be an infection you have at the moment that needs treatment. Or it could be an older infection that you’ve already dealt with. Even if you have completed treatment for a syphilis infection, you’ll get a positive result from the EIA test.

If you get a positive EIA, we’ll advise you to go to your local sexual health clinic for further tests. 

The RPR (rapid plasma reagin) test is used for people who’ve told us they have had syphilis before. This test checks for antibodies that your body produces in response to an active syphilis infection. These antibodies slowly reduce in your body after the infection is treated. As we use just a few drops of blood for our tests, we can only check if these antibodies are present or not. We cannot tell you a level of reagin antibodies.

 If you get a positive result from an RPR test, we’ll recommend you visit your local sexual health clinic for additional tests and guidance on whether treatment is needed.

Written by Helen Burkitt. Senior Sexual Health and Contraception Nurse
Reviewed by Abi Degg. Sexual Health and Contraception Nurse
Last updated at: 05 February 2024
Published on: 03 April 2023