What is the TPPA (Treponema pallidum particle agglutination) test?

The TPPA test is a laboratory blood test that detects antibodies specifically directed against Treponema pallidum, the bacterium responsible for syphilis. It works by identifying antibody–particle agglutination, which indicates prior exposure to the organism.

This test is highly specific and is used as a confirmatory test, not a screening tool. Once positive, TPPA antibodies usually remain detectable for life, even after successful treatment.

Because of this, TPPA confirms exposure but does not determine whether the infection is currently active.

Why do I need a TPPA test?

Initial syphilis screening tests can occasionally produce false-positive results. A confirmatory test is therefore required to establish a definitive diagnosis.

You may need this test if you:

• Have a reactive syphilis screening test (RPR, VDRL, or EIA)
• Need confirmation of suspected syphilis infection
• Are undergoing sexual health assessment
• Are being assessed during pregnancy
• Have symptoms suggestive of syphilis
• Need clarification of previous exposure
• Require confirmation for clinical documentation

TPPA ensures diagnostic accuracy and appropriate clinical decision-making.

Benefits of the test

1. Highly specific for syphilis
   Confirms true exposure to Treponema pallidum.
2. Essential confirmatory test
   Used after positive screening results.
3. Reduces false-positive diagnoses
   Improves diagnostic confidence.
4. Reliable lifetime marker
   Remains positive after past infection.
5. Widely used in UK clinical practice
   Standard confirmatory syphilis test.
6. Supports pregnancy screening
   Confirms maternal infection history.
7. Simple blood-based testing
   Requires only one blood sample.
8. Clarifies infection history
   Helps distinguish true exposure from screening artefacts.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic
• Attend your appointment
• A clinician draws a blood sample
• Sample is sent to the laboratory
• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Book a mobile phlebotomist
• Blood sample taken at your home or hotel
• No need to attend a clinic
• Sample securely transported to the laboratory

Your results explained

Negative TPPA

• No antibodies to Treponema pallidum detected
• UK standard: Negative
• No evidence of past or current syphilis infection

Positive TPPA

• Antibodies to Treponema pallidum detected
• UK standard: Positive
• Confirms exposure to syphilis at some point

Interpretation note

• TPPA does not indicate whether infection is active
• Activity is assessed using non-treponemal tests (e.g. RPR or VDRL)