Treponema Pallidum Hemagglutination Assay (TPHA)
TPHA is a confirmatory test for syphilis that detects specific antibodies against Treponema pallidum. Unlike RPR, once positive, TPHA usually remains positive for life even after successful treatment.
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- Includes Doctor Consultation
- Physician-reviewed
- Same Day Collection
24 hours
Turnaround
Blood
Sample
What the Treponema Pallidum Hemagglutination Assay (TPHA) test tells you
TPHA looks for antibodies your immune system makes specifically against Treponema pallidum, the bacterium that causes syphilis. Because those antibodies are aimed at the organism itself rather than at the tissue damage it leaves behind, the test is described as treponemal, and it is highly specific for this one infection. A small blood sample is all that is needed, and the result is reported as reactive or non-reactive rather than as a measurement.
Syphilis is normally assessed with two different kinds of test together, because neither answers the whole question alone. Non-treponemal tests such as RPR reflect how active the infection is, and their strength falls after successful treatment. TPHA answers a different question: has this person's immune system ever met Treponema pallidum? Once reactive, it usually stays reactive for the rest of a person's life, even after the infection has been completely cured. That permanence is exactly what makes it a good confirmatory test and a poor test of cure.
A reactive TPHA is therefore read alongside the non-treponemal result, any history of previous syphilis treatment, your symptoms and your exposure history. Your doctor combines those pieces to judge whether this is an untreated infection needing treatment now, or a lasting mark in the immune memory from an episode already dealt with. Antibodies also take time to appear after exposure, so a non-reactive result taken soon after a possible exposure may need to be repeated before it can be relied on.
Confirmatory test after a positive RPR/VDRL screening. Also used for syphilis diagnosis in populations with a high pre-test probability.
- Confirming a positive screen
Screening tests such as RPR and VDRL can react for reasons other than syphilis. A reactive TPHA on the same sample makes a genuine treponemal infection far more likely.
- High specificity
Because the antibodies it detects are directed at Treponema pallidum itself, TPHA rarely reacts to unrelated conditions the way non-treponemal tests sometimes do.
- After a possible exposure
If you have had a sexual exposure that concerns you, or a partner has been diagnosed, TPHA is part of the assessment your doctor may arrange.
- Clarifying an unclear history
People often cannot recall whether an old infection was treated. A reactive result establishes that exposure happened, which shapes what is checked next.
Reasons your doctor may request the Treponema Pallidum Hemagglutination Assay (TPHA) test
Your doctor may order this test for any of the reasons below. Some are routine checks, others follow specific symptoms or an earlier result.
Confirming a screening result
- A reactive or borderline RPR or VDRL screening result that needs confirmation.
- Unexplained neurological or eye symptoms where late syphilis is one of the possibilities being considered.
Ulcers & rash
- A painless genital, oral or anal ulcer, or an unexplained rash involving the palms and soles.
Routine screening, partners & pregnancy
- A sexual partner who has been diagnosed with syphilis.
- Routine sexual health screening when you have a new partner or multiple partners.
- Screening in pregnancy, or before certain medical procedures.
A Reactive / Positive result means your immune system has met Treponema pallidum, but it does not say when. These antibodies usually persist for life, so the result stays reactive long after an infection has been treated successfully. That is why it is read together with a non-treponemal test such as RPR, your treatment history, your symptoms and your exposure history: those together show whether this is an untreated infection or a lasting mark from an episode already dealt with. Related conditions such as yaws and pinta, and rarely some autoimmune conditions, can also give a reactive result. A Non-Reactive / Negative result means no treponemal antibody was detected. Antibodies take time to develop, so a sample taken soon after a possible exposure may need repeating. TPHA does not track response to treatment, so your doctor decides the next step alongside your other results.
Medically reviewed by Dr Nirupama Sabhapathy
This test is reported descriptively rather than on a numeric scale: each finding below explains what your report may say.
No treponemal (syphilis) antibody found; soon after exposure, a repeat test may be needed.
Treponemal antibody present: syphilis at some point, current or treated; read with RPR.
Ranges are a guide: your physician interprets your result alongside your symptoms and history.
What a higher result can point to
- Current, untreated syphilis at any stage of the infection.
- Syphilis diagnosed and successfully treated in the past, since the antibodies persist.
- Infection with a related treponemal organism, such as the non-sexually transmitted conditions yaws and pinta seen in some tropical regions.
- Rare cross-reaction in certain autoimmune conditions or other spirochaetal infections, which is why the result is read with the clinical picture.
These are possibilities, not diagnoses. A single value outside the reference range is interpreted alongside your symptoms, history and other tests: your doctor decides what it means for you.
What this test cannot tell you
- A reactive result cannot say whether the infection is active now or was treated years ago; that distinction comes from non-treponemal testing and your treatment history.
- Antibodies take time to develop, so testing soon after a possible exposure can be non-reactive even when infection has occurred, and may need repeating.
- A non-reactive result carries no meaning beyond the absence of detectable treponemal antibodies.
- TPHA does not track response to treatment, so it is not used to decide whether therapy has worked.
Risks of the blood draw
- Mild bruising or brief soreness where the needle went in.
- Occasional lightheadedness, which settles after a few minutes of rest.
- Bleeding or infection at the site, which is rare with sterile single-use equipment.
- 1TPHA is a confirmatory syphilis test rather than a screening test on its own.
- 2Once reactive it usually stays reactive for life, even after successful treatment.
- 3It is interpreted together with a non-treponemal test such as RPR.
- 4Syphilis is treatable, and treatment decisions belong to your doctor once the full picture is reviewed.
- 5Testing very soon after exposure can miss an early infection.
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Frequently Asked Questions
Everything you need to know about the Treponema Pallidum Hemagglutination Assay (TPHA) test. Can't find what you're looking for?
Talk to our team→RPR and VDRL are non-treponemal screening tests that react to the body's response to infection, and their levels fall after successful treatment, so they are used to judge whether infection is active and to follow treatment. TPHA detects antibodies specific to Treponema pallidum and confirms a reactive screen, but it usually stays reactive for life. The two are read together.
It means no treponemal antibodies were detected in the sample, and it carries no meaning beyond that. If you had no recent exposure, it points away from past or present syphilis. Antibodies take some weeks to become detectable, so after a recent possible exposure your doctor may prefer to repeat the test later rather than rely on one early sample.
TPHA is the test used to confirm a reactive RPR or VDRL, so a non-reactive TPHA means the syphilis-specific antibodies were not found and the screening result is not confirmed. That points away from syphilis. Because antibodies take time to develop, though, your doctor may repeat both tests later if the exposure was recent or symptoms suggest early infection.
Possibly, and syphilis is treatable. Both tests being reactive points towards syphilis, but it may be an untreated infection or the lasting mark of one already treated. Your doctor decides from your treatment history, symptoms, exposure history and the RPR level. Mention any previous syphilis diagnosis or treatment and any recent antibiotics, since they change how the result is read.
Not by itself. A reactive result shows your immune system has encountered Treponema pallidum at some point. Whether the infection is active is judged from a non-treponemal test such as RPR, from your symptoms, and from whether you have been treated before. Your doctor puts those together.
Treatment clears the bacteria, but the memory cells that produce treponemal antibodies usually persist indefinitely. That is expected and is not a sign that treatment failed. Follow-up after treatment is done with non-treponemal testing, which does fall over time.
Rarely. Related treponemal infections such as yaws, which occur in some tropical regions and are not sexually transmitted, can react. Occasional cross-reactions have been described in certain autoimmune conditions. That is why a reactive result is always interpreted in context.
Not immediately. There is a window while the immune response develops during which the test can be non-reactive despite infection. If your exposure was recent, your doctor may repeat testing after an interval rather than acting on one early sample.
No. No fasting or dietary restriction is needed, you can take your usual medicines, and the sample can be given at any time of day. If you are testing because of a specific exposure, tell the team when it happened.
The TPHA test is AED 105, including a physician-reviewed report, with results usually within 24 hours. Home collection anywhere in Dubai is free when your order reaches AED 300 or includes a package; below that, a AED 100 home collection fee applies (AED 50 for a lab walk-in).