Which syphilis test is more sensitive for primary syphilis?

The MHA-TP (Microhemagglutination Test for Treponema pallidum) is considered the more sensitive test for detecting primary syphilis. During the early stages of syphilis, particularly in the primary phase, the body's immune response to the Treponema pallidum bacteria is still developing. The MHA-TP test specifically detects antibodies against the actual pathogen causing syphilis, leading to high sensitivity even during the initial infection stage.

This test is noteworthy for its ability to remain positive throughout all stages of syphilis, unlike non-treponemal tests such as VDRL (Venereal Diseases Research Laboratory) and RPR (Rapid Plasma Reagin), which can sometimes yield negative results in early primary syphilis due to the antibodies not being produced yet or in low titers. These non-treponemal tests are more useful for monitoring treatment response rather than for diagnosis at the very early stage of infection.

Furthermore, the Febrile agglutination test is primarily used for detecting certain types of febrile illnesses and does not specifically apply to the detection of syphilis, making it less relevant in this context. Thus, the sensitivity of the MHA-TP for