The RAPID 1-2-3® HEMA EXPRESS® SYPHILIS (the TEST) is an in vitro, rapid, qualitative, two site double antigen sandwich immunoassay for the detection of Treponema pallidum (syphilis) in human serum / plasma/whole blood specimen.
Syphilis is a sexually transmitted (venereal) disease caused by the spirochete Treponema pallidum. The disease can also be transmitted congenitally thereby attaining its importance in prenatal screening. After infection the host forms non-treponemal anti lipoidal antibodies (reagins) to the lipoidal material released from the damaged host cells as well as treponema specific antibodies. Serological Tests for non-treponemal antibodies such as VDRL, RPR, TRUST etc. are useful as screening tests for treponema specific antibodies such as TPHA, FTA-ABS, rapid treponema antibody Tests are gaining importance as screening as well as confirmatory Tests because they detect the presence of antibodies specific to Treponema pallidum.
PRINCIPLES OF THE TEST
The RAPID 1-2-3® HEMA EXPRESS® SYPHILIS TEST is a modified TPHA, which qualitatively detects the presence of IgM and IgG class of treponema specific antibodies during a syphilis infection in whole blood, serum or plasma specimens within 15 minutes.
The RAPID 1-2-3® HEMA EXPRESS® SYPHILIS TEST utilizes the principle of immunochromatography, a unique two site immunoassay on a membrane. As the test sample flows through the membrane assembly of the test device, the recombinant Treponemapallidum antigens colloidal gold conjugate forms a complex with Treponema specific antibodies in the sample. This complex moves further on the membrane to the test region where it is immobilized by the recombinant Treponemapallidum antigens coated on the membrane leading to the formation of a pink to deep purple colored band at the test region ‘T’ which confirms a positive test result. Absence of this colored band in test region ‘T’ indicates a negative test result. The remaining conjugate and unbound complex if any, along with rabbit IgG colloidal gold conjugate move further on the membrane and are subsequently immobilized by the goat anti-rabbit antibodies coated on the membrane at the control region, forming a colored band. This control band serves to validate the test results.