The FTA ABS blood test is used to either screen for or diagnose the presence of a bacteria called Treponema pallidum. This is the bacteria that is known to cause Syphilis. Several different types of these tests are available and antibody tests tend to be the most common that are ordered today.
An individual does not need to be showing the signs and symptoms of this STD in order for this test to be ordered. If they have a sexual partner who may be showing the signs and symptoms of Syphilis or if a persona has an active STD infection such as HIV, then they are considered to be at-risk for an infection and a test will be ordered. Anyone who has engaged in high-risk sexual behavior is recommended to have this test.
Women who are pregnant will also have the FTA ABS blood test ordered to eliminate the possibility of the bacteria being present. No test preparation is needed for this test.
How Is the Sample Collected For the FTA ABS Blood Test?
For most people, the technician will perform a standard blood test by taking a blood sample from an arm vein. If there is an affected area that may be a symptom of Syphilis, then the technician may also take a scraping from the area as part of the test. Depending on the clinical presentation of the signs and symptoms of the infection, a spinal tap may be ordered as well.
What Do the Test Results Mean?
For the antibody tests that detect Syphilis, a negative FTA ABS blood test means that there is probably no infection present. It is possible for the blood test to produce a negative result because no antibodies to the bacteria have formed. If there is a suspicion of exposure, then a follow-up test 3-7 days after the initial test may be recommended just to confirm the initial negative result.
The FTA ABS blood test is used when a positive antibody result occurs. The first screen that will be ordered is an RPR or VDRL screen. If the first screen comes back positive, the FTA ABS blood test will be ordered. Should the second screening come back as positive, then a diagnosis of Syphilis will be confirmed.
If the FTA ABS blood test comes back as negative, but the first screening was positive, then the first test may have produced a false positive result. It may also indicate that there was a previous Syphilis infection as antibodies can take up to 3 years to fully disappear after a successfully treatment protocol.
What If a CSF Test Was Ordered?
The CSF initial screening test is generally ordered when someone arrives showing the signs and symptoms of late or latent stage Syphilis. This typically means the bacteria have involved the central nervous system and the brain. When the FTA ABS blood test comes back as positive for the CSF screening, then this usually means that the bacteria have caused an infection of the nervous system.
A negative CSF result from the FTA ABS blood test typically means that there is no central nervous system infection present, but that there may still be an active STD in the body elsewhere.
Direct detection methods from scrapings are also a possibility. Negative results from a scraping can mean that there is no infection present. It may also mean that there wasn’t enough Syphilis bacteria in the sample to generate a positive result.
When Is the FTA ABS Blood Test Most Effective?
Most doctors will order the FTA ABS blood test in the first 90 days after a potential Syphilis exposure when one of the primary testing methods comes back with a positive result. From the 6 week to the 6 month time post-exposure, this test might be ordered as a primary detection method for the disease. It is also effective at discovering latent forms of the disease several years after exposure.
Results are typically available about 3-5 days after the test has concluded. All pregnant women are given this test because Syphilis contributes to low birth weights and the possibility of stillbirth. About 300 children every year are infected with congenital syphilis because their mothers passed the bacteria along during the birthing process. Congenital Syphilis may stay inactive or unnoticed until puberty.
Unlike other blood tests, the FTA ABS blood test is an effective screening tool for determining if there is a bacterial infection. Sometimes this test is required to receive a marriage license. If you have any questions or concerns about Syphilis and if it may be a problem for you, then be sure to ask your doctor about this test today.