RPR (Syphilis Testing)

What is a rapid plasma reagin (RPR) test?
A rapid plasma reagin (RPR) test is a blood test used to screen you for syphilis. It works by detecting the nonspecific antibodies that your body produces to fight the infection.
Syphilis is a sexually transmitted infection (STI), caused by the spirochete bacterium Treponema pallidum. It can be fatal if left untreated. Combined with specific antibody testing, the RPR test allows your doctor to confirm the diagnosis of active infection and start your treatment. This reduces the chances of complications and the spread of the disease by an infected but unaware person.
RPR test is required for USCIS?
The RPR test measures antibodies that are not specific only to syphilis, rather than the bacterium that causes disease itself. It can also be used to check the progress of treatment for active syphilis. After a course of effective antibiotic therapy, your doctor would expect to see the number of antibodies drop, and an RPR test could confirm this.
How is blood for the RPR test obtained?
Doctors obtain blood for the RPR test with a simple blood test called a venipuncture. This can be done in your doctor’s office or a lab. You don’t need to fast or take any other special measures before this test. The test involves the following steps:

  • A healthcare provider will ask you to sit in a comfortable chair or lie down on a cot or a gurney.
  • They then tie rubber tubing around your upper arm to help make your veins stand out. When they find your vein, they will swab the spot with rubbing alcohol to cleanse it and insert a needle into the vein. The needle may produce a sudden, sharp pain, but it typically doesn’t last long.
  • Once they have the blood sample, they’ll remove the needle from your vein, hold pressure on the puncture site for a few seconds, and offer you a bandage.

Risks of the RPR test
Venipuncture is minimally invasive and carries very few risks. Some people complain of soreness, bleeding, or bruising after the test. You can apply an ice pack to the puncture wound to help relieve these symptoms.
Some people may become light-headed or dizzy during the test. Tell the healthcare provider if your dizziness lasts longer than a few minutes.
Understanding your results
A normal RPR blood sample shows no antibodies to syphilis. However, your doctor cannot completely rule out syphilis if they see no antibodies. Once you’ve been infected, it takes some time for your immune system to create antibodies to fight the bacterium. Shortly after infection, a test may not yet show any antibodies. This is known as a false negative.
False negatives tend to be more common in the initial and end stages of infection. Among people who are in the secondary (middle) stage of infection, the RPR test result is nearly always positive.
The RPR test also can produce false-positive results, suggesting you have syphilis when you don’t. One reason for a false positive is the presence of another disease that produces antibodies similar to the ones that fight syphilis. A few of the conditions that can cause a false positive include the following:

  • HIV
  • Lyme disease
  • malaria
  • lupus
  • Due to the risk of false-positive results, your doctor will confirm the presence of syphilis with a second test, one that is specific for antibodies against the bacterium that causes syphilis, before starting your treatment. One such test is called the fluorescent treponemal antibody-absorption (FTA-ABS) test.

These tests will be an additional cost to you.