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Syphilis

Also known as: VDRL; RPR; FTA; TPHA
Formal name: Treponema pallidum (implicated pathogen)

At a Glance

Why Get Tested?

To screen for syphilis infection

When to Get Tested?

If you have symptoms of a syphilis infection, have a sexually transmitted disease (STD), or as part of screening before or during pregnancy

Sample Required?

Usually a scraping from a chancre (ulcer or sore) in the affected area, a blood sample from a vein, or a spinal tap (lumbar puncture), depending on the stage of the disease.

Test Preparation Needed?

None

The Test Sample

What is being tested?

The test is looking for evidence of Treponema pallidum, the bacterium that causes syphilis. Syphilis is a sexually transmitted disease. It is easily treated but can cause severe health problems if left untreated.

How is the sample collected for testing?

There are several different methods and tests for the identification of syphilis infection. A sample may be:

  • a scraping from a chancre (sore) on the affected area (the cervix, penis, anus or throat)
  • a blood sample from a vein in your arm to detect antibodies to syphilis in your blood
  • a spinal tap (lumbar puncture) may be necessary if you have late or latent stages of the disease to check for infection of the nervous system.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

How is it used?

The test is used to diagnose infection with syphilis.

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When is it requested?

A doctor may request the test:

  • when a chancre (ulcer or sore) is present on the genitals or throat
  • if a patient is being treated for another sexually transmitted disease, such as gonorrhoea
  • as part of screening before or during pregnancy, because untreated syphilis can infect and even kill a developing fetus or
  • if a patient complains of non-specific symptoms that resemble those of syphilis, to determine the exact cause of the illness.

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What does the test result mean?

Presence of the syphilis bacterium in the discharge from a chancre (a positive test) indicates the presence of an infection that requires treatment with a course of antibiotics.

The blood test detects the antibodies that the body produces to combat infection, so a positive test indicates that you have either a current or past infection. Results of RPR and VDRL tests are reported as reactive to a dilutional titre . The degree of titre elevation is not necessarily reliable for staging syphilis, but appropriate titre decline does define a successfully treated case. The blood test becomes positive 3-6 weeks after exposure to the bacteria but might not find antibodies for up to 90 days after infection. In addition, the antibodies remain in the body for years, so if one has had a past infection with syphilis and was treated, the test results could remain positive for life. If you have a past history of treated syphilis infection, this information should be shared with your doctor. This will ensure selection of the appropriate tests to determine whether or not current infection is present.

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Is there anything else I should know?

Some syphilis tests are not very sensitive and may occasionally give a falsely positive result. Positive tests should be checked by testing another sample if there is any concern about their validity. Occasional biological false-positives occur in the settings of injecting drug use, acute viral infections, and autoimmune disease.

Sexual partner(s) of patients with syphilis must get tested and treated.

People with syphilis often have higher risk for contracting other sexually transmitted diseases increases, including the risk of being infected with HIV, the virus that causes AIDS. HIV infected patients often show poor antibody response to infection and rapidly progress to late stages of the disease.

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Common Questions

1.  What are the symptoms of syphilis?

The first symptoms of syphilis may not be seen immediately. The primary stage begins within 10 days to three months of being infected. A sore, called a chancre, appears, usually on the part of the body exposed the partner’s ulcer, such as the penis or vagina. The chancre may be painless and go unnoticed, and it heals within a few weeks.

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2.  What will happen if I don’t get treated?

Secondary syphilis begins three to six weeks after the chancre appears. It is marked by a skin rash that usually heals in several weeks or months. There may be other symptoms as well, such as fever and sore throat. If untreated, syphilis may continue into a latent stage, during which you have no symptoms and are no longer contagious. However, about one-third of all cases will advance into the complications of late, or tertiary, syphilis. In these cases, the bacteria can damage the heart, eyes, brain, nervous system, bones, joints, or almost any other part of the body. This stage can last for years, with the final stage leading to mental illness, blindness, other neurological problems, heart disease, and death. Syphilis infection can be much more persistent and potentially more serious if the patient is HIV positive.

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3.  How is syphilis transmitted?

The bacterium is passed on through direct contact with a syphilis sore. This generally happens through sexual contact, such as vaginal, anal, or oral sex. An infected pregnant woman can spread the disease to her fetus, with serious and potentially fatal consequences for the baby.

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4.  How is it treated?

Syphilis can be treated with the antibiotic penicillin. Newly acquired infections can be cured easily. A longer treatment may be needed to cure someone who has been infected for more than a year. A previously treated person can become infected with syphilis a second time if exposed again.

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5.  How can syphilis be prevented?

Sexually active young men and women can reduce their risk of syphilis by reducing their numbers of partners and using condoms correctly and consistently during sexual intercourse.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.