About Our Syphilis Test
Purpose of the test
The purpose of syphilis testing is to identify a syphilis infection. Tests may be prescribed for screening, diagnosis, or monitoring after treatment:
- Screening: Screening tests check for syphilis in people without signs or symptoms of the disease. Groups who benefit from screening include those at high risk of contracting syphilis, as well as those more likely to transmit this infection to others.
- Diagnosis: Diagnostic testing is recommended if you have signs or symptoms that could be caused by syphilis. This STD can cause a wide range of symptoms, so doctors may recommend testing for syphilis even when symptoms aren’t severe or specific to this condition. Generally, diagnosing syphilis requires two tests: an initial screening test and a second confirmatory test.
- Monitoring: After treatment for syphilis, follow-up testing may be performed to make sure the infection is responding to treatment. Doctors typically monitor changes in certain antibody levels over time to confirm that treatment was effective.
What does our syphilis test measure?
Most syphilis tests detect antibodies produced by the immune system in response to infection with the bacterium Treponema pallidum. Blood tests look for these antibodies to determine whether a person has been infected with syphilis.
Two main types of antibody tests are used.
The first are called nontreponemal antibody tests. These tests detect antibodies produced during a syphilis infection, but they are not specific to the syphilis bacteria. Because these antibodies can also appear in other conditions, a positive result usually requires confirmation with another test.
Non-treponemal tests are also useful for monitoring response to treatment, because the levels of antibodies in the blood typically decrease after successful therapy.
Common nontreponemal tests include:
- Rapid plasma reagin (RPR) test: This test detects the reagin antibody, which is produced by the body in response to cell damage caused by the syphilis infection.
- Venereal Disease Research Laboratory (VDRL): A VDRL test measures antibodies that are produced within two weeks after an infected person develops an initial sore. VDRL testing can be performed on blood or spinal fluid.
The second type of test is the treponemal test. These detect antibodies that specifically target Treponema pallidum and are used to confirm a syphilis infection after an initial screening test.
Unlike nontreponemal antibodies, treponemal antibodies often remain detectable for life, even after successful treatment. Because of this, treponemal tests can’t determine whether an infection is current or occurred in the past.
In many testing approaches, a nontreponemal test is performed first, followed by a treponemal test to confirm the result. With advances in technology, some laboratories use the opposite approach, called reverse sequence testing, which starts with a treponemal test and then confirms active infection using a nontreponemal test.
Less commonly, tests may look directly for the syphilis bacterium or its genetic material. These tests include:
- Darkfield microscopy: This method examines fluid from a syphilis sore under a special microscope to directly visualize the bacteria obtained from a syphilitic lesion
- Polymerase chain reaction (PCR) testing: This testing detects the genetic material (DNA) of Treponema pallidum and is most useful in detecting early onset syphilis.
When should I get a syphilis test?
People without symptoms are usually tested for syphilis only if they have an increased risk of infection or of transmitting the infection to others.
Regular screening for syphilis is recommended for several groups:
- Women and anyone with a vagina: Screening may be recommended if you have an increased risk of infection, such as having multiple sexual partners, a partner diagnosed with syphilis, history of incarceration, or living in an area with higher rates of infection.
- Pregnant people: Testing is recommended at first prenatal visit to help prevent congenital syphilis (syphilis passed on to a newborn). Additional testing 28 weeks later in pregnancy may be recommended for those at increased risk (substance use, STI during pregnancy,multiple partners/new partner), or living in areas with higher infection rates.
- Men and anyone with a penis: Sexually active people in this group who have sex with women should be screened for syphilis or who may be at risk (history of incarceration or sex work, race/ethnicity, or under 29 years old). Men who have sex with men should be screened at least once a year or more frequently(every three to six months if at risk.
- People diagnosed with HIV: Sexually active people living with HIV should be screened for syphilis during their initial HIV evaluation and at least annually afterward, depending on their risk and local infection rates.
- Transgender and Gender Diverse Persons: Due to social and structural barriers, many fail to receive appropriate care, increasing susceptibility to STIs and HIV. Gender-based screening should be based on anatomy with frequent rescreening depending on risk level.
Anyone with symptoms should receive diagnostic testing. Without treatment, syphilis infection progresses through three stages: primary syphilis, secondary syphilis, and tertiary syphilis.
These three stages are separated by periods in which no symptoms are present. In any stage of syphilis, the infection can spread to the brain and nervous system, called neurosyphilis. Syphilis can also spread to the eye, called ocular syphilis, or to the ears, called otosyphilis.
The signs and symptoms of syphilis vary based on the stage of infection:
Syphilis Symptoms
| Disease Stage | Symptoms |
| Primary Syphilis |
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| Secondary Syphilis |
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| Tertiary Syphilis |
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| Neurosyphilis |
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| Ocular Syphilis |
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| Otosyphilis |
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Finding a Syphilis Test
How to get tested
Testing to detect syphilis is typically ordered by a health care professional. To screen you without symptoms, a doctor or other health care professional can evaluate your risk of syphilis and suggest a schedule for screening.
Syphilis testing can be performed in a medical setting such as a hospital, doctor’s office, or clinic, or at a health program in an individual’s community. Tests can also be ordered online.
You can order a home STD testing kit (with treatment included) with testing by a Clinical Laboratory Improvement Amendments (CLIA)-approved lab.
Can I take the test at home?
At-home test kits are available for people who want to screen for syphilis from home. These kits typically involve collecting a small blood sample, often via a finger prick, and mailing it to a laboratory for analysis.
If an at-home test result is positive, additional testing may be recommended to confirm the diagnosis and guide treatment. A health care professional can help interpret the results and recommend appropriate next steps.
How much does the test cost?
When ordered by a doctor, the cost of testing for syphilis may be covered by your health care insurance. Talk to your health insurance provider about specific costs, which may include copays and deductibles.
Other times, syphilis testing may be paid for out of pocket. In addition to the cost of the test itself, you may be responsible for costs such as an exam fee, technician fees, and the price of any test conducted at the same time.
If you are concerned about the cost of syphilis testing, it may be helpful to contact a local health department or community-based organizations that provide low-cost or free STD testing.
Taking a Syphilis Test
Syphilis testing is most often performed using a blood sample. Testing can also be performed using fluid swabbed from a syphilis sore or spinal fluid. Spinal fluid is collected in a special procedure called a lumbar puncture.
Samples used for syphilis testing are generally collected by a medical professional.
Before the test
No special preparations are necessary before a syphilis test that uses a sample of blood or fluid from a sore.
Before a lumbar puncture, you may be instructed to go to the bathroom to empty your bladder and bowels.
During the test
What happens during the testing process depends on the type of sample being collected.
- Blood sample: Blood is drawn from a vein in your arm using a small needle. The sample is collected into a vial or tube for laboratory testing.
- Sore sample: A swab or brush is used to collect fluid from a syphilis sore to be sent for testing. The collection process may be uncomfortable, but it’s very brief.
- Spinal fluid sample: A health care provider cleans an area on your back and injects an anesthetic that reduces pain during the procedure. Once your back is numb, a thin needle is inserted into the spine, and a small sample of spinal fluid is withdrawn for testing. This procedure takes about five minutes to complete.
After the test
After a blood draw, a bandage may be placed over the site to reduce bleeding or bruising. Most people can return to their normal activities right away.
If fluid is collected from a sore, there are typically no restrictions after the test.
After a lumbar puncture, you may be asked to lie down for a short time to help reduce the risk of a headache. You may feel sore at the puncture site for a while.