Which serological test can be used to detect Treponema pallidum infection?

Serologic testing is the preferred method of diagnosis. Two types of serologic tests are used: treponemal and nontreponemal assays. Traditional serologic screening for syphilis begins with a nontreponemal test followed by a treponemal test to confirm reactive results.

What are the serological tests of syphilis?

Serological tests are divided into two types: nontreponemal and treponemal. Nontreponemal tests include the rapid plasma reagin (RPR) test and the Venereal Disease Research Laboratory (VDRL) test, both of which are based on the detection in the blood of syphilis reagin (a type of serum antibody).

What is the best diagnostic test for Treponema pallidum?

The direct fluorescent antibody test for T pallidum is easier to perform than dark-field microscopy. It detects antigen and, thus, does not require the presence of motile treponemes. It is the most specific test for the diagnosis of syphilis when lesions are present.

What are the two major kinds of serologic tests for syphilis?

Serologic tests for syphilis require the use of two tests: nontreponemal tests that use a nonspecific cardiolipin antigen and confirmatory tests that use specific T. pallidum antigens (Table 1). A nontreponemal test, such as VDRL or RPR, may be used for screening.

Which is the best test for Treponema pallidum?

Treponemal tests available in the United States include the microhemagglutination assay for T. pallidum (MHA-TP), the T. pallidum particle agglutination (TPPA), the T. pallidum hemagglutination assay (TPHA), and the fluorescent treponemal antibody absorption assay (FTAABS).

How are treponemal tests used to diagnose syphilis?

Treponemal tests detect antibodies to specific antigenic components of T. pallidum. Traditionally, non‐treponemal tests detected antibodies to putative nonspecific antigens (primarily cardiolipin) produced by the host in response to syphilis infection.

When does Treponema pallidum IgM become undetectable?

After therapy in primary and secondary syphilis, T. pallidum IgM antibodies decrease rapidly, becoming undetectable within 6–12 months [8]. Several studies suggest that decreasing IgM levels indicate adequacy of treatment [9]. Merlin et al [10] demonstrated the absence of IgM antibodies in 84% of patients with previously treated syphilis.

What’s the difference between RPR and Treponema pallidum?

In contrast to older methods, such as the rapid plasma reagin (RPR) test, that use phospholipid (nontreponemal) antigens, newer serologic tests use specific T. pallidum antigens. These new technologies have flooded international markets because of their automation.