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Syphilis Ab

Order Code CH182
Turnaround Time 24 hours
Test Includes

Syphilis Ab

Specimen Requirements
Specimen Source
Serum, Plasma
Transport Container
(Specimen Container)

SST (Tiger Top)/ Lithium Heparin/ Sodium Heparin/ Dipotassium EDTA/ Tripotassium EDTA

Preferred Specimens
Minimum Volume (uL)
.5 mL
Collection Instructions
(Transport Temperature)
Transport Refrigerated (cold packs)
Specimen Stability
Temperature Period
Room temperature 72 hours
Refrigerated 7 days
Frozen 30 days
Test Details
chemiluminescent microparticle immunoassay
Clinical Significance

Syphilis is caused by infection with the bacterium Treponema pallidum (TP), which is transmitted primarily by sexual contact or congenitally. The disease can present in different clinically defined stages (primary, secondary, latent, and tertiary); the latent phase is asymptomatic.

Upon infection with TP, an immune response develops that is directed not only against antigens specific to TP but also antigens released during the TP-mediated cellular damage. Two types of tests have been developed as aids to diagnose syphilis, treponemal and nontreponemal. A positive treponemal test result is an indication for an acute, latent, or past infection with TP. Nontreponemal tests are especially valuable for monitoring disease activity and therapy response. It is common practice that reactive test results of either a treponemal or nontreponemal test are confirmed by a test of the complementary test type to enhance diagnostic accuracy.

The Alinity i Syphilis TP assay is a treponemal test that detects IgG and IgM antibodies to TP. Two different algorithms, which combine a treponemal with a nontreponemal test, are used as an aid in the diagnosis of syphilis. The algorithm starting with the treponemal test is called reverse screening algorithm and has been implemented in laboratories due to the availability of automated treponemal tests.

Samples reactive in a treponemal test are subjected to a nontreponemal supplementary test (e.g., Rapid Plasma Reagin [RPR]). The reverse screening algorithm for syphilis testing can identify persons previously treated for syphilis and those with untreated or incompletely treated syphilis. Discordant treponemal-reactive, RPR-nonreactive results should be reflexed to a second treponemal test (e.g., Treponema Pallidum Particle Agglutination [TP-PA]) for further evaluation.

Reference Ranges