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RPR with Reflex, completion of reverse cascade for specimens known positive for T. pallidum treponemal antibodies

CPT: 86592


  • Syphilis
  • Treponema pallidum

Special Instructions

This test is intended only for specimens that have tested positive for Treponema pallidum antibodies prior to submission.

Related Documents

Specimen Requirements




1.4 mL

Minimum Volume

0.75 mL (Note: This volume does not allow for repeat testing.)


Gel-barrier tube; serum transfer tube


If tube other than a gel-barrier tube is used, transfer separated serum to a labeled plastic tube. Do not freeze gel-barrier tube (pour off serum first).

Storage Instructions

Room temperature

Stability Requirements



Room temperature

7 days


7 days


7 days

Freeze/thaw cycles

Stable x2

Causes for Rejection

Hemolysis; lipemia; gross bacterial contamination; plasma specimen

Test Details


This panel is intended only for specimens that have tested positive for Treponema pallidum antibodies prior to submission. This panel will complete the recommended reverse cascade for screening and diagnosis of syphilis. Specimens negative by RPR will reflex to T. pallidum antibody testing by TrepSure™.


False-positive RPR reactions can occur due to pregnancy, drug addiction, collagen vascular disease, and advanced age. In addition, false-positive results have been noted in the presence of numerous nonsyphilis infectious diseases, including HCV infection, inflammatory states, or in individuals who have been recently vaccinated against influenza virus.


Charcoal flocculation and enzyme immunoassay


Association of Public Health Laboratories Laboratory Diagnostic Testing for Treponema pallidum: Expert Consultation Meeting Summary Report. August 2018.
Association of Public Health Laboratories Suggested Reporting Language for Syphilis Serology Testing. December 2015.

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