Syphilis RPR

The Syphilis RPR test contains 1 test with 1 biomarker.

Description: The rapid plasma reagin test is used to determine if a person has been infected with syphilis. An RPR can be used to monitor treatment for syphilis and the effectiveness of syphilis treatment. Syphilis testing is a two-part test. The first round of testing for syphilis is an RPR test. If these results come back positive, a second round of testing will be required. A positive RPR result will be followed by a second method that will be used to confirm the results. If the second syphilis test comes back positive, the affected person will be diagnosed with syphilis. If the second test comes back negative, it could mean that the first test is a false positive and more testing may be necessary.

Also Known As: Rapid Plasma Reagin with Reflex to Titer, Syphilis RPR, Syphilis Titer test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required


A positive RPR screen must be followed by a specific treponemal antibody test (e.g., FTA-ABS):

A positive result on the second method confirms the screening result and the affected person is diagnosed with syphilis.

A negative result on the treponemal test may mean that the initial RPR test was falsely positive. Further testing and investigation may be done to determine the cause of the false positive.


False-positive results have been associated in patients with infections, pregnancy, autoimmune disease, old age, Gaucher disease, and malignancy.

When is a Syphilis RPR test ordered?

When a person shows signs and symptoms of syphilis, a syphilis test may be done.

Regardless of symptoms, a person should be tested for syphilis if they:

  • Are being treated for gonorrhea or another sexually transmitted disease?
  • If a woman is pregnant, she should be seen during the first prenatal visit, then again in the third trimester and at the time of delivery if she is at high risk.
  • Are a man who has sex with other males; testing should be done at least once a year or every 3-6 months if the risk is significant.
  • Engages in high-risk sexual behavior, such as having intercourse with several partners without protection.
  • If you have HIV, you should get tested when you're initially diagnosed and then at least once a year after that; if you're at high risk, you should get tested more frequently.
  • Has one or more partners who have tested positive for syphilis
  • Officials from the Department of Public Health have told him or her that he or she has been exposed to an infected partner.

When a person has been treated for syphilis, the CDC recommends doing follow-up testing, such as assessing antibody levels, to ensure that the therapy was successful and the infection was cured.

What does a Syphilis RPR blood test check for?

Syphilis is a bacterial infection caused by Treponema pallidum that is primarily spread during sexual activity, such as by direct contact with a syphilis sore. The majority of common syphilis tests can detect antibodies in the blood that were produced in response to a T. pallidum infection. Some less common methods can be used to locate the bacterium or its genetic components.

Syphilis is easily treated with medications, but if left untreated, it can cause serious health concerns. A mother who is afflicted can convey the disease to her unborn child, which can have serious and even fatal effects for the newborn.

With syphilis, there are numerous stages that can occur:

  • The primary stage of syphilis begins about 2-3 weeks following infection. One or more chancres emerge, usually on the body portion exposed to the chancre of the sexual partner, such as the penis or vaginal area. The chancre, on the other hand, is usually painless and may go unnoticed, especially if it is in the rectum or on the cervix, and it goes away within 4-6 weeks, mending whether or not the infected person is treated.
  • If primary syphilis is left untreated, secondary syphilis can develop anywhere from 6 weeks to 6 months after the chancre initially emerges. It is characterized by a rough, red, and speckled skin rash that appears regularly on the palms of the hands and the bottoms of the feet and does not itch. Fever, weariness, enlarged lymph nodes, sore throat, and body aches are some of the other symptoms that can occur.
  • Secondary syphilis can progress to a latent stage, during which an infected individual has no symptoms but still retains the infection, and this stage can remain for years if left untreated. If left untreated, roughly 15% of persons will develop late, or tertiary, syphilis issues. Bacteria can harm the heart, eyes, brain, neurological system, bones, joints, and practically any other component of the body in these situations. Neurosyphilis is a disease that affects the central nervous system. Tertiary syphilis can linger for years, leading to mental illness, blindness, other neurological issues, heart disease, and death in the ultimate stage.
  • If left untreated, syphilis progresses.

The basic and secondary stages of syphilis are the most contagious. About a third of the approximately 63,000 new cases of syphilis reported to the CDC in 2014 were main or secondary stage syphilis. Eighty-three percent of these cases included guys having intercourse with other men.

Antibiotics, usually penicillin, can be used to cure syphilis. Infections that have been acquired recently can be rapidly healed; however, someone who has been infected for more than a year may require prolonged therapy.

Lab tests often ordered with a Syphilis RPR test:

  • HIV Antibody
  • HIV Antigen
  • Gonorrhea
  • Chlamydia
  • Herpes 1 and 2
  • Trichomonas
  • STD Panel

Conditions where a Syphilis RPR test is recommended:

  • Sexually Transmitted Diseases
  • Syphilis
  • Gonorrhea
  • Chlamydia
  • Herpes 1
  • Herpes 2
  • HIV and AIDS
  • Pregnancy

How does my health care provider use a Syphilis RPR test?

Syphilis tests are used to detect and/or diagnose infection with the bacterium Treponema pallidum, which causes syphilis.

There are a variety of tests to choose from. The most common type of test is an antibody test.

Antibody tests identify antibodies in the blood and, occasionally, in the cerebrospinal fluid. Nontreponemal antibody test and treponemal antibody test are the two types of syphilis tests available. Syphilis screening can be done with any type, but it must be followed by a second test that employs a different approach to confirm a positive result and identify active syphilis:

Antibodies that aren't specifically directed towards the Treponema pallidum bacterium are detected by nontreponemal antibody testing. The body produces these antibodies when a person has syphilis, but they can also be produced in a variety of other situations. Because the tests are non-specific, false-positive findings can be produced by things like IV drug usage, pregnancy, Lyme disease, certain types of pneumonia, malaria, tuberculosis, or certain autoimmune disorders like lupus. A positive screening result must be double-checked with a more detailed test. Nontreponemal testing include the following:

RPR—in addition to screening, this test can be used to track syphilis therapy. Antibody levels are tested for this reason. When an initial test for treponemal antibodies is positive, it can also be used to confirm the existence of an active infection.

VDRL—in addition to blood, this test is largely used to identify neurosyphilis in the CSF.

Antibodies to T. pallidum are detected by treponemal antibody tests, which are blood tests. Because they are extremely specific for syphilis, they are unlikely to produce a positive result in other diseases. Once a person is infected and these antibodies form, they remain in the bloodstream for the rest of their lives. Nontreponemal antibodies, on the other hand, usually vanish within 3 years in a properly treated person. As a result, a positive treponemal screening result must be followed by a nontreponemal test in order to distinguish between an active infection and one that has been successfully treated in the past. FTA-ABS is a treponemal antibody test that is beneficial after the first 3-4 weeks after exposure. It can be used to assess antibodies to T. pallidum in the CSF to assist diagnose neurosyphilis in addition to blood testing.

  • TP-PA—instead of FTA-ABS, this test is sometimes used because it is more specific and has less false positives.
  • Another confirmatory approach is MHA-TP, which is presently used considerably less frequently.
  • Immunoassays—Several automated tests have been developed in recent years, making them useful for screening applications.

What do my Syphilis test results mean?

A negative blood test indicates that there is most likely no infection. A negative screening test, on the other hand, simply states that there was no evidence of disease at the time of the test. Antibodies may not be detected for several weeks following bacterial contact. If a person is aware that he or she has been exposed, or if the risk of infection remains high, additional testing may be required. It is also critical for persons who are at a higher risk of contracting syphilis to get regular screening tests to check for infection.

A particular treponemal antibody test must be performed after a positive RPR or VDRL screen:

The infected person is diagnosed with syphilis once a positive result on the second method confirms the screening result.

A negative treponemal test result could indicate that the initial RPR or VDRL test was incorrectly positive. To discover the reason of the false positive, more testing and investigation may be conducted.

A treponemal antibody test, on the other hand, will be used as an initial test by a healthcare practitioner or laboratory. A positive result indicates the presence of syphilis antibodies in the blood, but because treponemal antibodies stay positive even after an infection is treated, it does not indicate whether the person is now afflicted or has previously been infected. Nontreponemal antibodies found with an RPR, on the other hand, usually vanish after 3 years in a properly treated person. If the initial treponemal test is positive, an RPR can be used to determine whether the infection is active or past. A positive RPR in this scenario would establish that the person has been exposed to syphilis and, if not previously treated, has an ongoing infection or, if treatment occurred more than 3 years ago, possible re-infection.

The results of one or more RPR titers may be used to monitor treatment and/or determine if treatment was successful. Antibodies to syphilis should be decreased after therapy. If the RPR was 1:256 before therapy, a number of 1:16 after treatment would indicate a reduced amount of antibody. The affected person may have a persistent infection or was reinfected if the titer stays the same or rises. The results can also be transformed to a whole number or reported as dilutions.

Nontreponemal antibodies fade away over time after effective treatment, whereas treponemal antibodies remain in the blood for the rest of one's life.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: RPR Monitor with Reflex to Titer, Syphilis

Rpr (Monitor)

RPR (rapid plasma reagin) is a screening test for syphilis. It looks for antibodies that are present in the blood of people who have the disease.
*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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