Treponema pallidum haemagglutination assay (TPHA)

TPHA with Treponema pallidum antigen detects antibodies to Treponema pallidum and is a treponemal syphilis test. It is used together with non-treponemal tests and clinical information. This approach helps distinguish situations requiring further investigation from those in which antibodies relate to a past, treated infection.

Treponemal antibodies often persist for a long time after treatment. TPHA does not independently establish syphilis activity and is not intended to assess treatment effectiveness through a falling titre. The doctor assesses the result together with symptoms, medical history and other investigations. The reference values of the individual laboratory are used for comparison, and changes over time are considered during follow-up.

• Detect treponemal antibodies within a diagnostic algorithm.
• Complement investigation after a reactive screening test.