Syphilis is a sexually transmitted infection caused by Treponema pallidum.

The TPHA test detects specific antibodies by hemagglutination reaction using sensitized red blood cells coated with T. pallidum antigens.

Clinical uses include:

Confirming syphilis infection after a positive screening test (VDRL, RPR).

Differentiating true positives from false positives in non‑treponemal tests.

Supporting diagnosis in latent, treated, or past infections.

TPHA remains positive for life in most patients, even after successful treatment, so it is not useful for monitoring therapy.

Analyte: Antibodies against Treponema pallidum in serum.

Normal Result: Negative (no hemagglutination).

Abnormal Findings:

Positive TPHA: Indicates current or past syphilis infection.

Persistent positivity: Seen even after treatment, reflecting exposure rather than active disease.

Clinical Use:

Provides a specific confirmatory marker for syphilis diagnosis.

Helps guide screening, confirmation, and epidemiological studies.

Supports infectious disease, dermatology, neurology, and sexual health evaluations.