VDRL; RPR (Rapid Plasma Reagin)
Understanding VDRL; RPR (Rapid Plasma Reagin)
What is VDRL; RPR (Rapid Plasma Reagin)?
A VDRL; RPR (Rapid Plasma Reagin) is a blood test that looks for antibodies (specific proteins) against a bacterial infection called syphilis, a sexually transmitted disease (STD). This test helps screen for active syphilis infection and also helps monitor response to ongoing treatment.
Syphilis infection is caused by the bacteria called Treponema pallidum. The infection spreads through contact with a syphilic sore, also called a chancre, usually during sexual activities. It can also be transmitted from the mother to the baby during pregnancy or childbirth. If not treated appropriately, syphilis can stay in the body for years and cause significant harm to the internal organs.
The first and most common sign of syphilis is a painless sore that develops where the bacteria entered the body. The sore typically appears within three weeks of exposure. It usually occurs in the reproductive and oral (mouth) area, and may go unnoticed if it is hidden inside the body. Syphilis can progress through four different stages and causes different symptoms in each stage. The infection is highly contagious in the first and second stages and can easily be transmitted to your sexual partners.
A VDRL; RPR (Rapid Plasma Reagin) for syphilis is performed when you have symptoms suggestive of this infection. These symptoms include small and painless sores near the site of infection, skin rash, fever, swollen lymph glands, hair loss, headaches, muscle ache, tiredness, etc. A VDRL; RPR test is also recommended to screen for the disease in certain groups of people at an increased risk of infection or of transmitting the infection to others.
Non-reactive RPR tests without clinical evidence of syphilis may suggest no current infection or an effectively treated infection. A false positive RPR (means positive results in the absence of syphilis) can be encountered in tuberculosis, malaria, and viral pneumonia. A reactive RPR test suggests past or present infections with the bacteria that cause syphilis. The VDRL; RPR (Rapid Plasma Reagin) test helps determine if the treatment against syphilis is working.
After a course of effective antibiotic therapy, usually the number of antibodies are expected to decrease, and VDRL; RPR (Rapid Plasma Reagin) may help confirm this. So if you are a sexually active adult with HIV or AIDS, you may need to get tested at least once a year. Doctors often use a VDRL; RPR (Rapid Plasma Reagin) to screen pregnant women for syphilis. A syphilis screening test is usually demanded by different states for anyone applying for a marriage certificate.
A VDRL; RPR (Rapid Plasma Reagin) doesn’t require you to fast or stop taking any medications. If your doctor wants you to make an exception, they will let you know before your test. However, avoid alcohol consumption prior to the test. Drinking alcohol within 24 hours of the test can give a false-negative result.
Test results may vary depending on your age, gender, health history, and other things. Talk to your doctor about your specific test results. Narrate your complete medical history to help the doctor correlate your clinical and laboratory findings. The results will help them evaluate your medical condition; make recommendations for diet, exercise, or medication; and formulate an overall treatment plan.
What is VDRL; RPR (Rapid Plasma Reagin) used for?
A VDRL; RPR (Rapid Plasma Reagin) test is done:
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To screen for syphilis in people having symptoms of sexually transmitted infections.
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To screen people who are at risk of exposure to syphilis such as having another STD or HIV infection, homosexual men having a sexual partner diagnosed with syphilis, or indulged in high-risk sexual activity.
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To screen pregnant women for syphilis.
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To monitor the ongoing treatment response for syphilis.
What does VDRL; RPR (Rapid Plasma Reagin) measure?
A VDRL; RPR (Rapid Plasma Reagin) test looks for antibodies (specific proteins) that react to syphilis in the blood. This means the test doesn't find the actual bacteria that cause syphilis. Instead, it looks for antibodies against substances given off by cells that have been harmed by the bacteria. Antibodies are a specific type of protein produced by your immune system to fight off any invader such as bacteria, virus or toxins. Detecting these antibodies can help your doctors know if you have syphilis. Untreated syphilis can spread to your eyes, blood vessels, heart and brain. But it can be easily cured if treated in the early stages.
Interpreting VDRL; RPR (Rapid Plasma Reagin) results
Interpretations
Negative: A negative ("non-reactive") RPR test result is compatible with a person not having syphilis.
The result of this test can be “positive” or “negative”. But there are some cases where the results can be false positive or false negative.
A negative ("non-reactive") RPR test result suggests that a person is not having syphilis. However, the body does not always produce antibodies specifically in response to the syphilis bacteria, so the test is not always accurate. False-negatives test result may occur in people with early- and late-stage syphilis. Because of that other tests are required to confirm the results.
A false positive RPR (means positive results in the absence of syphilis) can be encountered in infectious mononucleosis, tuberculosis, leprosy, malaria, lupus erythematosus, vaccinia, and viral pneumonia. Pregnancy, autoimmune diseases, and narcotic addictions may give false-positive results. Also, this test may give false-positive result in pinta, yaws, bejel, and other treponemal diseases.
RPR test is also used to monitor treatment response. Treatment response is generally indicated by a 4-fold (2-tube dilution) reduction in rapid plasma reagin (RPR) titer (e.g., from 1:32 to 1:8). For proper interpretation of RPR results, titers should be obtained using the same testing method and, preferably, at the same testing laboratory.
Failure of nontreponemal test titers to decline 4-fold within 6 months after therapy for primary or secondary syphilis may be indicative of treatment failure. Patients whose titers remain serofast should be reevaluated for HIV infection.