What the Patient Should Know About Syphilis and RPR Lab Test Procedure and Results

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Who May Need This Test?

Contrary to popular belief, there are many reasons that the physician may order the PRP lab test to screen for syphilis. Pregnant women, those with a diagnosis of another sexually transmitted disease and patients exhibiting symptoms of this STD will most commonly have this test ordered. Patients being treated for syphilis may also need to test following treatment to ensure that the antibiotics are effective. According to Medline Plus, many states also require those applying for a marriage license to have this test.

RPR Lab Test Procedure and Results

The PRP lab test is a blood test procedure that is fairly simple. No special preparation is required for this type of testing. An antiseptic is used to clean the site where the specimen is to be collected and blood is drawn. However, the testing procedure for the infant or small child may be quite different and the sample is not collected via a needle. This alternate procedure involves making a small puncture to the skin and catching blood in a specimen tube or test strip. Results are read as either positive or negative. Positive results may not always mean that the patient has syphilis. The blood test screens for antibodies as a result of infection. Once infected, the individual will have those antibodies and can continue to test positive long after the infection has been successfully treated. Negative results can also occur with an infected patient.

Special Considerations

Various factors can play a critical role in the RPR lab test procedure and results. False positive and/or false negative results can be linked to more than just a previous infection. Those with certain diseases or conditions may test positive for this sexually transmitted disease. Certain types of pneumonia, HIV, Lyme disease or malaria can cause a false positive result. There are also limitations to the ability of the VDRL to detect syphilis in some infected individuals. This includes the early stages and late stages of this STD.

Associated Tests

No test is 100% accurate, so the RPR test isn’t the only tool that may be utilized to diagnose syphilis. Scraping of lesions or chancres, fluorescent antibody and assay tests may be ordered to assist in confirming a positive result. These tests may also be ordered when the patient has a negative result, despite indicative signs and symptoms. In addition to this, the physician may recommend testing for other sexually transmitted diseases, such as HIV and hepatitis C. This is because syphilis increases the risks of infection of these particular STDs.


RPR Test. Medline Plus. National Institute of Health. Updated 25, June 2010. Viewed 12, July 2010. https://www.nlm.nih.gov/medlineplus/ency/article/003533.htm

Syphilis: The Test. Lab Tests Online. Modified 18, June 2010. Viewed 12, July 2010. https://www.labtestsonline.org/understanding/analytes/syphilis/test.html