Chye ClinicTPHA vs RPR: Which Syphilis Test Do You Need?
A syphilis result in Malaysia usually comes back as two lines: RPR (or VDRL) and TPHA. People often ask which one they should have. The honest answer is both, because each test answers a question the other cannot.
The short answer
RPR tells the doctor whether syphilis is active and how active it is. TPHA confirms that the infection is syphilis and not something that only looks like it on a blood test. A diagnosis rests on the pair, read together with your history.
What RPR measures
RPR is a non-treponemal test. It does not look for the syphilis bacterium itself. It picks up antibodies the body makes against material released when cells are damaged by the infection. VDRL is an older test of the same kind.
A reactive RPR comes with a titre, written as a ratio such as 1:8 or 1:64. The higher the second number, the more active the infection. That number is what treatment is later judged against.
Because RPR measures a reaction rather than the bacterium, other things can make it reactive. Pregnancy, autoimmune conditions such as lupus, some recent viral infections and older age all produce false positives, usually at low titres.
What TPHA measures
TPHA is a treponemal test. It detects antibodies against Treponema pallidum, the bacterium that causes syphilis, so a positive result is specific to it. TPPA, EIA and CLIA are related tests that do the same job.
The catch is that TPHA usually stays positive for life, even after syphilis has been fully treated. On its own it cannot tell an infection from last month apart from one cured ten years ago.
Reading the two results together
| RPR | TPHA | What it usually means |
|---|---|---|
| Non-reactive | Negative | No sign of syphilis. If the exposure was recent, it may be too early to show, and a repeat test is needed. |
| Reactive | Positive | Syphilis that needs treatment, unless you were treated before and the titre is falling as expected. |
| Non-reactive | Positive | Most often syphilis that was treated in the past. Less often, a very early or a long-standing untreated infection, so your history decides what happens next. |
| Reactive | Negative | Usually a false positive RPR. The doctor looks for the cause and may repeat it or use a different treponemal test. |
Why some labs run TPHA first
Some laboratories now start with an automated treponemal test and only run RPR if it is positive. This is called reverse screening. The order changes, the conclusion does not: you still end up with both results, read the same way.
When to test after a possible exposure
Both tests rely on antibodies, and the body takes time to make them. Most infections show up within about three to six weeks, and a few take up to three months. A test around six weeks after the exposure catches most, and a repeat at three months covers the rest.
If you have a sore, do not wait for the window to pass. The first sign of syphilis is a painless sore that heals by itself, and a doctor who sees it can act on the examination and test you the same day.
After treatment
RPR is repeated at intervals after treatment, commonly at three, six and twelve months. The titre should fall by at least fourfold, for example from 1:32 to 1:8. TPHA is not repeated, because it will stay positive.
Keep a copy of your results and the date you were treated. Any future syphilis test will show a positive TPHA, and that record saves you from being treated again for an infection you no longer have.
Syphilis testing at Chye Clinic
Syphilis is in every STD profile at the clinic, starting with the standard profile at RM 125, which also covers HIV, herpes simplex 2 and hepatitis B and C. The doctor who orders the test explains the result, including what your RPR titre means for treatment. More on symptoms, stages and treatment is on the syphilis page.
Chye Clinic, Kepong Baru
Questions about a syphilis result?
Send what your report says, or ask about testing. Pick what fits and the message is written for you.
- Daily, 9:00am to 8:00pm
- Walk in, no appointment needed
- Confidential, same doctors every visit
Your messageHi, I have a syphilis test result (RPR and TPHA) and would like it explained.
Talk to our doctor nowOpens WhatsApp with your message ready to send, and you can edit it first. Nothing is submitted from this page, and no name, number or appointment time is asked for here.
48, Jalan Lang Kuning, 52100 Kepong Baru, Kuala Lumpur. How to find us
This article is general information and does not replace an assessment by a doctor who knows your history.
Syphilis at Chye Clinic
Syphilis is curable, and early syphilis is usually cured by a single injection. It is missed so often because the first sore is painless and heals on its own while the infection continues.