Syphilis (RPR + FTA-ABS)

The Syphilis (RPR + FTA-ABS) panel contains 2 tests with 2 biomarkers.

Syphilis (RPR + FTA-ABS)

• FTA-ABS - Treponema pallidum Ab (Confirmation for Syphilis RPR test).
• Syphilis RPR ( RPR (Monitor) with Reflex to Titer)

FTA-ABS - Treponema pallidum Ab

Clinical Significance

The FTA-ABS is a specific treponemal assay to detect antibody to t. Pallidum. The FTA-ABS becomes reactive 4-6 weeks after infection. Unlike the nontreponemal tests, once the FTA-ABS test becomes reactive, it will remain reactive for many years. Since the reactivity found with the FTA-ABS does not indicate response to therapy, it is not suitable for monitoring treatment. The FTA-ABS test does not distinguish between syphillis and other treponematoses such as yaws, pinta and bejil.

The treponemal antibody test (FTA-ABS) is often used as an initial test. A positive result indicates the presence of syphilis antibodies in the blood, but since treponemal antibodies remain positive even after an infection has been treated, it does not indicate whether the person has a current infection or was infected in the past. Conversely, nontreponemal antibodies as detected with an RPR typically disappear in an adequately treated person after about 3 years. Thus, if an initial treponemal test is positive, an RPR can be performed to differentiate between an active or past infection. In this case, a positive RPR would confirm that the person has been exposed to syphilis and, if not treated previously, has an active infection or, if treatment had occurred more than 3 years ago, possible re-infection.

Alternative Name(s) 

Treponemal pallidum, Fluorescent Treponemal Antigen, Syphilis

Syphilis RPR ( RPR (Monitor) with Reflex to Titer)

Reference Range(s)

Non-Reactive

Clinical Significance

This is a non-treponemal screening test for syphilis. False positive results may occur due to systemic lupus erythematosus, leprosy, brucellosis, atypical pneumonia, typhus, yaws, pinta, or pregnancy. Monitoring of RPR is helpful in assessing effectiveness of therapy.

IMPORTANT

A positive RPR screen and a positive result on the FTA-ABS confirms the screening result and the affected person is diagnosed with syphilis.

A negative result on the treponemal test may mean that the initial RPR test was falsely positive. Further testing and investigation may be done to determine the cause of the false positive.

Limitations

False-positive results have been associated in patients with infections, pregnancy, autoimmune disease, old age, Gaucher disease, and malignancy.

Alternative Name(s) 

Syphilis