Syphilis Antibody Cascading Reflex
Also known as: Treponema Ab, Treponema pallidum, Reverse Algorithm, Syphilis, T. pallidum
Use
This test provides a sequential (“cascading reflex”) approach for syphilis serologic diagnosis. An initial treponemal antibody screening (EIA) is performed. If that result is equivocal or positive, an RPR screen is done. If the RPR is reactive, an RPR titer is performed; if the RPR screen is non‑reactive, then T. pallidum antibody by particle agglutination (TP‑PA) is performed.
Special Instructions
If the initial treponemal antibody result is equivocal or positive, reflex testing is automatically triggered per algorithm without need for re‑order. Requires an adequate volume of serum drawn and appropriate transport.
Limitations
Individuals previously treated for syphilis often remain antibody‑positive for life; antibody testing is not useful for monitoring treatment response or re‑infection. Reflex testing may prolong overall time to final result depending on sequential testing steps and specimen routing.
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
3‑6 mL blood
Minimum Volume
1.4 mL Serum
Container
Red‑Top Tube
Causes for Rejection
Hemolysis; Lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 Days |
| Refrigerated | 7 Days |
| Frozen | 30 Days |