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Turnaround Time
1 - 4 days
Use
This test is intended to support screening and diagnosis of syphilis infections. This test aligns with the CDC-supported reverse serologic testing algorithm for syphilis using a combination of both treponemal and nontreponemal antibody tests. The reverse syphilis testing algorithm begins with a treponemal antibody assay. Positive samples reflex to RPR (nontreponemal). If the RPR is positive, RPR titer will be determined. If the RPR is negative, a second treponemal antibody assay will be performed to confirm the presence of treponemal antibodies. Interpretation of results obtained must take into account patient symptoms and clinical history.
Test Includes
Reflex to qualitative rapid plasma reagin (RPR) on positives
Limitations
Treponemal antibodies typically persist for life despite treatment; thus, this assay cannot be used to monitor response to treatment or to assess treatment outcomes. False positive treponemal antibody results have been observed in individuals with nonsyphilis treponemal infections (bejel, pinta, yaws).
Methodology
Enzyme immunoassay (EIA) with reflex to charcoal flocculation if reactive
References
Association of Public Health Laboratories (APHL). Suggested Reporting Language for Syphilis Serological Testing, 2nd ed. August 2020. Accessed via APHL website at https://www.aphl.org/programs/infectious_disease/std/Pages/Syphilis.aspx.
Workowski KA, Bachman LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021 Jul 23;70(4):1-187.34292926
Additional Information
Treponemal antibody (CIA) | RPR | RPR titer | Treponemal antibody (EIA) | Interpretation |
|---|---|---|---|---|
Nonreactive | Not done | Not done | Not done | No laboratory evidence of syphilis. If recent exposure is suspected, submit a new sample for testing in 2-4 weeks. |
Reactive | Nonreactive | Not done | Nonreactive | Treponemal antibodies not confirmed. Inconclusive for syphilis; potentially early syphilis, possible false positive. If recent exposure is suspected, submit a new sample for testing in 2-4 weeks. If clinical suspicion is low no further evaluation is necessary. |
Reactive | Nonreactive | Not done | Reactive | Treponemal antibodies detected. Consistent with past or current (potentially early) syphilis. Clinical evaluation should be performed to identify current signs and symptoms or past history of infection. If past history of treatment reported, no further management is needed unless symptomatic or recent exposure suspected. If no symptoms or past history of treatment, and if recent exposure is suspected, submit a new sample for testing in 2-4 weeks. |
Reactive | Reactive | 1:1 or greater | Not done | Treponemal and nontreponemal antibodies detected. Consistent with past or current syphilis. Clinical evaluation should be performed to identify current signs and symptoms or past history of infection. |
Specimen Requirements
Information on collection, storage, and volume
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Storage Instructions
Room temperature
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination; plasma specimen