What test is used to confirm the presence of syphilis?

The dark-field illumination test is specifically designed to visualize live Treponema pallidum organisms, which are the causative agents of syphilis. This method relies on the unique properties of the bacteria and allows for direct observation of the spirochetes in a fluid sample, typically taken from a syphilis sore. Confirmatory diagnosis often relies on identifying the actual organism, making this testing method highly specific.

While other tests mentioned can provide useful information about the infection, they do not directly confirm the presence of Treponema pallidum. The rapid plasma reagin (RPR) test and similar non-treponemal tests can indicate a syphilis infection but may produce false positives due to various reasons. Bacterial culture can be used in research but is not practical for diagnosing syphilis in clinical settings, and the ELISA test assesses antibodies and not the organisms themselves, making it less definitive for direct confirmation. Hence, dark-field illumination remains the gold standard for directly confirming syphilis.