Syphilis is one of the most common sexually transmitted diseases (STDs). It is a bacterial infection spread through vaginal, oral, or anal sex with an infected person. Syphilis develops in stages that can last for weeks, months, or even years. The stages may be separated by long periods of apparent good health.
Syphilis usually starts with a small, painless sore, called a chancre, on the genitals, anus, or mouth. In the next stage, you may have flu-like symptoms and/or a rash. Later stages of syphilis can damage the brain, heart, spinal cord, and other organs. Syphilis tests can help diagnose syphilis in the early stages of infection when the disease is easiest to treat.
What is the test used for?
Syphilis tests are used to screen for and diagnose syphilis.
Screening tests for syphilis include:
Rapid plasma reagin (RPR), a syphilis blood test that looks for antibodies to the syphilis bacteria. Antibodies are proteins made by the immune system to fight foreign substance, like bacteria.
Venereal disease research laboratory (VDRL) test, which also checks for syphilis antibodies. A VDRL test can be done on blood or spinal fluid.
If a screening test comes back positive, you will need more testing to rule out or confirm a syphilis diagnosis. Most of these follow up tests will also look for syphilis antibodies. Sometimes, a healthcare provider will use a test that looks for actual syphilis bacteria, instead of the antibodies. Tests that look for the actual bacteria are used less often because they can only be done in specialized labs by specially trained health care professionals.
HOW WILL THE TEST BE PERFORMED?
A syphilis test is usually in the form of a blood test. During a syphilis blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
More advanced stages of syphilis can affect the brain and spinal cord. If your symptoms show your disease might be in a more advanced stage, your health care provider may order a syphilis test on your cerebrospinal fluid (CSF). CSF is a clear liquid found in your brain and spinal cord.
For this test, your CSF will be collected through a procedure called a lumbar puncture, also known as a spinal tap. During the procedure:
You will lie on your side or sit on an exam table.
A health care provider will clean your back and inject an anesthetic into your skin, so you won't feel pain during the procedure. Your provider may put a numbing cream on your back before this injection.
Once the area on your back is completely numb, your provider will insert a thin, hollow needle between two vertebrae in your lower spine. Vertebrae are the small backbones that make up your spine.
Your provider will withdraw a small amount of cerebrospinal fluid for testing. This will take about five minutes.
You'll need to stay very still while the fluid is being withdrawn.
Your provider may ask you to lie on your back for an hour or two after the procedure. This may prevent you from getting a headache afterward.
WHY GET TESTED?
You may need a syphilis test if your sexual partner has been diagnosed with syphilis and/or you have symptoms of the disease. Symptoms usually appear about two to three weeks after infection and include:
Small, painless sore (chancre) on the genitals, anus, or mouth
Rough, red rash, usually on the palms of the hands or the bottom of the feet
Even if you don't have symptoms, you may need a test if you are at a higher risk of infection. Risk factors include having:
Multiple sex partners
A partner with multiple sex partners
Unprotected sex (sex without using a condom)
An HIV/AIDS infection
Another sexually transmitted disease, such as gonorrhea
You may also need this test if you are pregnant. Syphilis can be passed from a mother to her unborn baby. A syphilis infection can cause serious, and sometimes deadly, complications to infants. Women who have risk factors for syphilis should be tested again in the third trimester of pregnancy (28–32 weeks) and again at delivery.