Home Biomarkers TPHA (TREPONEMA PALLIDUM)

TPHA (TREPONEMA PALLIDUM)

STDs Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: STDs

Overview

TPHA (Treponema pallidum hemagglutination assay) is a treponemal serologic test that detects antibodies specific to Treponema pallidum, the bacterium that causes syphilis. The assay measures whether treponemal antibodies are present (usually reported as reactive/positive or non‑reactive/negative). It is used to support diagnosis of current or past syphilis infection and to screen individuals with symptoms or risk factors. Indications include genital ulcers, unexplained rash (including palms/soles), lymphadenopathy, neurologic or ocular symptoms, or routine STI screening in pregnancy and high‑risk groups. Results can vary by stage of infection (may be negative in very early primary syphilis), prior treated infection (often stays positive for life), and in neonates (maternal IgG transfer). HIV co‑infection and immune status can alter serologic responses.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Which profile is the test included in: STDs (sexually transmitted diseases) screening/profile.
What symptoms may indicate a need for this test: genital ulcers, unexplained rash (including palms/soles), mucocutaneous lesions, lymphadenopathy, neurological or ocular signs, or pregnancy screening and exposure risk.
What conditions it may diagnose/monitor: current or past syphilis (Treponema pallidum) infection; used in conjunction with non‑treponemal tests to stage disease and assess treatment response.
What could be the reasons for abnormal levels: true infection (active or past), recent infection in the window period (may be initially negative), prior treated infection (usually remains positive), or false results due to technical factors.
Biological meaning of abnormal values: reactive indicates presence of treponemal antibodies (exposure/infection); non‑reactive indicates no detectable treponemal antibodies.
What behaviors/lifestyle can cause abnormal values: unprotected sexual contact, multiple sexual partners, sex work, intravenous drug use with shared needles.
What family history may indicate a need for the test: maternal syphilis during pregnancy or known household exposure to a person with syphilis (risk to neonate).

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Understanding Test Results

Reactive (positive): indicates detectable treponemal antibodies consistent with exposure to Treponema pallidum.
A reactive TPHA usually means current or past syphilis infection; it does not reliably distinguish active disease from previously treated infection because treponemal antibodies often persist for years or lifelong.
Reactive TPHA should be interpreted with clinical findings and usually followed by or correlated with a non‑treponemal test (e.g., RPR or VDRL) to assess activity and for baseline titers for treatment monitoring.
Very high titers on quantitative treponemal assays (if reported) may suggest recent/active infection but are not definitive.

Normal Range

Non‑reactive Negative (no units)

FAQs

Q: What does TPHA positive mean?

A: TPHA positive means blood contains treponemal antibodies against Treponema pallidum, the bacterium that causes syphilis. It indicates current or past infection but does not distinguish active disease from treated infection. Further testing (non-treponemal tests like VDRL/RPR), clinical assessment, and treatment history are needed to determine activity and need for therapy. Positive results may persist lifelong after treatment.

Q: What is the reason of TPHA positive?

A: TPHA positivity indicates presence of antibodies to Treponema pallidum, showing current or past exposure to syphilis. A positive result can reflect active infection, treated (resolved) infection, or congenital exposure; it often remains positive for life after infection. Rare false-positives may occur with other treponemal infections, autoimmune disorders, or laboratory error. Correlation with symptoms and non-treponemal tests helps determine activity.

Q: What is the TPHA Treponema pallidum test?

A: The TPHA (Treponema pallidum hemagglutination) test is a blood test that detects antibodies to Treponema pallidum, the bacterium that causes syphilis. It’s a treponemal assay used to confirm infection after screening tests (such as VDRL/RPR). TPHA is highly sensitive and specific but often remains positive for life, so it cannot reliably distinguish active from past treated infection.

Q: Is TPHA positive for life?

A: Yes TPHA detects treponemal (syphilis) antibodies and in most people remains positive for life even after successful treatment. Treponemal tests aren’t used to monitor therapy; non-treponemal tests (RPR/VDRL) are used because their titres usually fall with effective treatment. Rarely, early-treated cases or immunosuppressed patients may revert to negative, but lifelong positivity is typical.

Q: What is the normal range of TPHA?

A: TPHA is reported as non‑reactive (negative) or reactive (positive); a normal result is non‑reactive/negative. When titres are reported, values below the laboratory cutoff are considered negative many labs treat titres below 1:80 as non‑reactive. A reactive TPHA indicates current or past Treponema pallidum exposure and should be interpreted with clinical history and other tests.

Q: Is syphilis an STD?

A: Yes. Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum, spread mainly through sexual contact and from mother to fetus. It progresses through stages (primary painless sore, secondary rash, latent, tertiary complications) and can be diagnosed with blood tests. Early infection is curable with antibiotics—usually penicillin—so prompt testing and treatment are essential to prevent serious long‑term damage.