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Syphilis: Treponemal Antibodies With Reflex to RPR and RPR Titer, Reverse Screening and Diagnosis Algorithm

CPT

86780

Synonyms
  • Syphilis
  • Treponemal
  • Syphilis
  • Trep-Sure™
  • Treponemal
  • Syphilis
  • Treponemal
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  • Updated on 03/24/2025

Test Details

Methodology

Chemiluminescent immunoassay with reflex to charcoal flocculation (RPR)

Enzyme immunoassay (EIA) with reflex to charcoal flocculation if reactive

Chemiluminescent immunoassay with reflex to charcoal flocculation (RPR)

Result Turnaround Time

1 - 4 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Documents

Test Includes

Treponemal antibody by chemiluminescent immunoassay with reflex of positive specimens to RPR. If RPR is positive, RPR titer will be performed. If RPR is negative, a second treponemal antibody test (TPPA) will be performed. 

Reflex to qualitative rapid plasma reagin (RPR) on positives

Treponemal antibody by chemiluminescent immunoassay with reflex of positive specimens to RPR. If RPR is positive, RPR titer will be performed. If RPR is negative, a second treponemal antibody test (TPPA) will be performed. 

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.

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).

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. PubMed 34292926
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
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. PubMed 34292926

Custom Additional Information

Treponemal antibody (CIA)RPRRPR titerTreponemal antibody (TPPA)Interpretation
NonreactiveNot doneNot doneNot doneNo laboratory evidence of syphilis. If recent exposure is suspected, submit a new sample for testing in 2-4 weeks.
ReactiveNonreactiveNot doneNonreactiveTreponemal 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.
ReactiveNonreactiveNot doneReactiveTreponemal 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.
ReactiveReactive1:1 or greaterNot doneTreponemal 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.

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.

Treponemal antibody (CIA) RPR RPR titer Treponemal antibody (TPPA) 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

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

Stability Requirements

TemperaturePeriod
Room temperature14 days
Refrigerated14 days
Frozen14 days
Freeze/thaw cyclesStable x3

Storage Instructions

Room temperature

Causes for Rejection

Hemolysis; lipemia; gross bacterial contamination; plasma specimen

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
082345 T pallidum Screening Cascade 47236-5 082356 T pallidum Antibodies 47236-5
Order Code082345
Order Code NameT pallidum Screening Cascade
Order Loinc47236-5
Result Code082356
Result Code NameT pallidum Antibodies
UofM
Result LOINC47236-5
Reflex Table for T pallidum Antibodies
Order Code Order Name Result Code Result Name UofM Result LOINC
Reflex 1 006099 RPR 006097 RPR 20507-0
Reflex 1
Order Code006099
Order NameRPR
Result Code006097
Result NameRPR
UofM
Result LOINC20507-0
Reflex Table for T pallidum Antibodies
Order Code Order Name Result Code Result Name UofM Result LOINC
Reflex 1 006099 RPR 006097 RPR 20507-0
Reflex 1
Order Code006099
Order NameRPR
Result Code006097
Result NameRPR
UofM
Result LOINC20507-0
Reflex Table for T pallidum Antibodies
Order Code Order Name Result Code Result Name UofM Result LOINC
Reflex 1 006099 RPR 006097 RPR 20507-0
Reflex 1
Order Code006099
Order NameRPR
Result Code006097
Result NameRPR
UofM
Result LOINC20507-0