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Test Code LAB3617 Syphilis Antibody Screen with Cascading Reflex (Diagnosis) Patient >18 months old

Infectious

Performing Laboratory

Barnes-Jewish Hospital

Methodology

Electrochemiluminescence Immunoassay (ECLIA)

Testing Algorithm:

Treponemal Ab is performed and if Positive, then qualitative RPR is performed. If RPR is Positive, RPR Titer is performed.  If RPR is Negative, Treponemal Ab by Particle Agglutination (TPPA) is performed. All additional testing is reflexed and performed at an additional change.

Literature References:

  1. Larsen SA, Hunter EF, Kraus SJ. A manual of tests for syphilis. Washington, DC: American Public Health Association, 1990.
  2. Elecsys Syphilis, Roche Diagnostics. 2026-01 v4.0
  3. Alere IMPACT Rapid Plasmin Reagin (RPR) Card Test Package Insert, Alere North America LLC, 30 South Keller Rd., Orlando, FL 32810 11/12/2015.
  4. Papp JR, Park IU, Fakile Y, Pereira L, Pillay A, Bolan GA. CDC Laboratory Recommendations for Syphilis Testing, United States, 2024. MMWR Recomm Rep. 2024 Feb 8;73(1):1-32

Specimen Requirements

Specimen Type: Serum

Container/Tube: Plain red top, Red/Grey or Gold top

Specimen Volume: Full tube, 1mL minimum

Day(s) Test Set Up

Monday through Sunday
Turnaround Time:
Stat: ED, L&D ordered STAT – 2 hours

Routine: Same Day

Test Classification and CPT Coding

CPT code

Test

86780

Treponemal AB

86592

RPR, if appropriate

86593

RPR Titer, if appropriate

86780

Treponemal Ab (TPPA), if appropriate

Reference Values

Reference: Negative

Treponemal Ab, RPR and TPPA Reported as Negative, Positive

RPR Titer reported as doubling dilution ratio 1:1, 1:2, 1:4, 1:8, 1:16, etc.
Once Treponemal Ab is Positive, it remains positive for life. Order RPR Monitoring (LAB3618)  in patients with known history of syphilis

 

Specimen Transport Temperature

Ambient

Special Instructions

For BJH Laboratory Use Only
Laboratory Processing Instructions:

Specimens will be put on the Cobas automation line.  If reflex testing is needed specimen will go to the MAN1-S1-OBS1 rack

LOINC Code Information

Name

LOINC Code

Treponemal Antibody

22587-0

RPR

22461-8

RPR Titer

22461-8

Treponema Ab -Particle Agglutination(TPPA)