Health

Rapid plasma reagin test for diagnosis of syphilis

The rapid plasma reagin test is similar to a conventional blood test, so it carries few risks. We explain what it consists of and what it is for.

Rapid plasma reagin test for diagnosis of syphilis

The rapid plasma reagin test is a test to diagnose antibodies to syphilis. It is a simple test that is carried out from a conventional blood test. It has been an important advantage in the control of this disease in recent years.

Syphilis is a sexually transmitted infection caused by a bacteria called Treponema pallidum. Despite the existence of treatment, it continues to be an important cause of morbidity and mortality.

Syphilis is easily spread. In many cases, the contagion is due to the lack of knowledge of the pathology. Therefore, in this article we explain what the rapid plasma reagin test consists of and what its advantages are.

What is syphilis?

Syphilis, as we noted in the introduction, is a sexually transmitted disease. The cause is a spirochete-type bacteria called Treponema pallidum. This infection is transmitted by contacting infectious sores that appear on the genitals, rectum, anus, or even the mouth.

It can also be transmitted during pregnancy, from mother to child. Or even through blood transfusions. It has symptomatic stages and completely asymptomatic periods that make its diagnosis more complex.

Shortly after infection, primary syphilis occurs. In this stage, fever, muscle aches, general malaise and swollen glands may appear. Also typical is a lesion called a chancre, which is the ulcer through which the infection is transmitted.

This ulcer is painless and goes unnoticed by the patient. This is when the asymptomatic period begins if no treatment is instituted. Syphilis remains latent, spreading.

As the years go by, damage occurs to all organs. It can lead to blindness, paralysis, numbness, and even death. That is why it is important to diagnose it early. Treatment is very simple and effective, but it should be done as soon as possible.

Rapid plasma reagin test for diagnosis of syphilis

The bacterium that causes syphilis is a spirochete, named for its shape.

What is the rapid plasma reagin test?

The rapid plasma reagin test detects specific antibodies in the blood. They are antibodies that the body synthesizes against substances in other cells, damaged by the bacterium Treponema pallidum.

That is, the bacteria attack the cells of the body in the first instance. These cells, when damaged, secrete substances for which the immune system synthesizes specific antibodies. Therefore, these antibodies only appear when you are already fighting the infection.

The rapid plasma reagin test helps identify active syphilis. However, it is not definitive, but rather serves to guide the diagnosis. If antibodies are detected, it is usual that other more specific tests are requested.

This test is also used to study the progress of the disease after establishing a therapeutic approach. When the treatment works, the antibodies in the blood go down. On the other hand, the rapid plasma reagin test is used in sexually active people as a means of screening.

Rapid plasma reagin test and pregnancy

Syphilis can be transmitted during pregnancy, from the mother to the fetus. This infection poses many risks to the baby. In fact, it increases the probability of miscarriages.

For this reason, in some countries the rapid plasma reagin test is required to detect infection during pregnancy. In places where this test is not part of the protocol, it is performed if risk factors are detected in the mother.

How is the rapid plasma reagin test performed?

The rapid plasma reagin test is similar to a conventional blood test. The first thing is to draw blood from the patient’s vein. To do this, a small plastic ribbon is tied around the arm that makes it easier to find the glass.

The skin is then cleansed with an antiseptic. A small needle is inserted into the area selected for the puncture. It is not necessary to obtain a large blood sample, as a small tube is usually sufficient.

The blood is sent to a laboratory that performs the test. All this procedure does not require any type of previous preparation.

Interpretation of results

The rapid plasma reagin test can give different results. It is determined to be normal or non-reactive when no antibody to syphilis is found in the blood. This is how the San Diego Health specialists explain it.

However, this requires certain considerations. That the result is negative does not completely rule out that the person is infected with syphilis. In the early stages of the disease, the body may not have produced antibodies yet.

There may even be low-titer antibodies, so they will be undetectable. This situation can lead to months with a false negative on the test.

It is also possible that, right after treatment, the rapid plasma reagin test will also not detect antibodies. That is why it is recommended to repeat the test after a couple of weeks.

Also, the best time to do it is in the intermediate stages of syphilis. That is, once enough time has passed for the body to generate the antibodies, albeit before treatment.

Rapid plasma reagin test results are influenced by other infections. There are certain pathologies in which antibodies similar to those of syphilis are synthesized. For example, malaria, HIV, Lyme disease, and lupus.

Rapid plasma reagin test for diagnosis of syphilis

Measuring antibodies has a margin of error. Some pathologies produce similar responses in the body that laboratory tests cannot distinguish.

Is the test at risk?

The rapid plasma reagin test is simple and safe. However, taking a blood sample carries some small risks. For example, bleeding from the puncture site, bruising, or feeling dizzy.

Although it is very unlikely, there can also be infections. What we must bear in mind is that the test is not exclusive for syphilis and can present false negatives or false positives. Therefore, additional tests are required to confirm the diagnosis.

One of the tests that is usually carried out in a confirmatory way is the fluorescent treponemal antibody absorption (FTA-ABS). It is a test that looks more specifically for antibodies against syphilis.

Syphilis must be detected early

The thing to remember about the rapid plasma reagin test is that it is an initial test for the detection of syphilis. It is a test that identifies antibodies against infection, but is not as specific.

Therefore, when a positive result appears, additional tests are often required to confirm. In addition, if the result is negative, but the clinical suspicion is high, it may also be necessary to repeat the test or include a different one.

Nevertheless, the rapid plasma reagin test is useful. The reason is that syphilis is a contagious but treatable infection. Therefore, detecting it early and establishing treatment can help prevent serious complications.