Getting tested for syphilis is straightforward: it usually requires a simple blood draw, and you can get one at your primary care doctor’s office, a sexual health clinic, or through an at-home test kit. Results from a rapid test can come back in minutes, while standard lab work typically takes a few days. The key is knowing when to test, since syphilis antibodies take time to show up after exposure.
What the Test Involves
The most common syphilis test is a blood test. A phlebotomist draws a small tube of blood from your arm, and the sample is sent to a lab where it’s checked for antibodies your immune system produces in response to the infection. That’s it. No urine sample, no uncomfortable swab (in most cases).
There are two categories of blood tests used together. The first type, called a nontreponemal test (RPR or VDRL), looks for antibodies that appear when the infection is active. These tests produce a numerical result, or titer, that reflects how active the disease is. The titer drops after successful treatment, so it’s also used to monitor whether treatment worked. The second type, called a treponemal test, looks for antibodies directed specifically at the syphilis bacteria. A positive treponemal test confirms you’ve been infected at some point, but it can’t tell whether the infection is recent, old, or already treated, because these antibodies often stay in your blood for life.
Most labs and clinics use both types together. One confirms infection, and the other helps determine whether the disease is currently active.
If you have a visible sore (chancre) or rash, your provider may also swab the lesion directly. The fluid is tested using a DNA-based method that can detect the syphilis bacteria itself, which is especially useful in early primary syphilis when blood antibodies haven’t fully developed yet.
When to Get Tested After Exposure
Syphilis has an incubation period of about 10 to 90 days, with the average around 21 days. During this window, your body may not yet produce enough antibodies for a blood test to detect. If you test too early after a potential exposure, you could get a negative result even if you’re infected.
For the most reliable results, wait at least 3 to 4 weeks after a suspected exposure before getting a blood test. If your first test is negative but your risk was high, repeating the test at 6 weeks or 3 months gives more confidence. If a sore appears before then, go in right away, since a lesion swab can catch the infection before blood tests turn positive.
Where to Go
You have several options, depending on your budget and comfort level:
- Your primary care doctor or OB-GYN. You can request a syphilis test at any routine visit. It’s often bundled into a standard STI panel alongside tests for HIV, chlamydia, and gonorrhea.
- Sexual health or STI clinics. Many local health departments and community clinics offer free or low-cost syphilis testing. The CDC’s GetTested tool (gettested.cdc.gov) lets you search for nearby clinics by zip code. These clinics provide confidential testing and don’t require insurance.
- Urgent care centers and commercial labs. Walk-in clinics and national lab chains offer syphilis testing, often without a doctor’s referral. Without insurance, expect to pay roughly $30 to $100 depending on the facility and whether you’re ordering a single test or a full STI panel.
- At-home test kits. The FDA authorized the first over-the-counter at-home syphilis test, the First To Know Syphilis Test by NOWDiagnostics, which detects syphilis antibodies from a finger-prick blood sample. Mail-in test kits from online services are another option: you collect a sample at home and send it to a lab for processing.
Rapid Tests vs. Lab Tests
Rapid point-of-care tests use a finger prick and can give results in 10 to 20 minutes, similar to a rapid HIV test. These are increasingly available at clinics and community health settings, and they’re useful for getting a quick answer on the spot. However, a reactive rapid test is typically confirmed with a standard lab-based blood test before treatment decisions are made.
Standard lab tests sent for processing generally return results within 1 to 5 business days, depending on the lab and your location. Your provider or the clinic will contact you with results, or you may be able to check them through an online patient portal.
What a False Positive Looks Like
Nontreponemal tests (RPR and VDRL) can occasionally produce false positives. This happens because these tests detect a general type of antibody that your body also produces during other conditions. Known causes of false positive results include autoimmune diseases (especially lupus and antiphospholipid syndrome), pregnancy, other acute infections, and sometimes older age. In a large retrospective study of nearly 36,000 tests, autoimmune diseases were identified as a leading driver of biologically false-positive syphilis results.
This is exactly why clinics use two types of tests together. If your nontreponemal test comes back positive, a treponemal test is run to confirm. If the treponemal test is negative, the initial result was likely a false positive. Your provider may also consider your medical history and any autoimmune conditions before interpreting results.
Who Should Get Screened Regularly
Some people benefit from routine syphilis screening even without symptoms, since syphilis can be silent for months or years. CDC screening guidelines recommend testing for:
- All pregnant women at the first prenatal visit, with repeat testing at 28 weeks and at delivery for those at increased risk
- Men who have sex with men at least once a year, and every 3 to 6 months if at higher risk
- People living with HIV at their first evaluation and at least annually after that
- Anyone at increased risk due to factors like multiple sexual partners, a history of STIs, transactional sex work, or a history of incarceration
Transgender and gender diverse individuals are advised to consider at least annual screening based on their sexual behaviors and exposure risk.
What Happens After a Positive Result
If both your nontreponemal and treponemal tests come back positive, your provider will determine the stage of infection based on your symptoms, sexual history, and the antibody titer level. Syphilis is treated with antibiotics, and early-stage infections are typically cured with a single treatment. Later stages may require a longer course.
After treatment, you’ll be asked to return for follow-up blood tests to make sure the antibody titer is dropping, which confirms the infection is clearing. Your nontreponemal titer should decline steadily over the months following treatment. The treponemal test, on the other hand, will likely remain positive for life, even after successful treatment. This means a past infection can show up on future screenings, but the nontreponemal test will distinguish between a treated past infection and an active one.
If you test positive, any recent sexual partners should also be tested and treated. Many clinics offer partner notification services to help with this process confidentially.