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Test Code RPRT Rapid Plasma Reagin (RPR), Response to Therapy, Serum

Reporting Name

RPR, Response to Therapy, S

Useful For

Determining the current disease status and evaluating response to therapy for syphilis

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Advisory Information

This test is not intended for medical-legal use.


This test is for monitoring response to therapy in patients treated for syphilis infection. This test should not be used as a primary diagnostic approach for syphilis.


To screen for undiagnosed syphilis infection, order SYPGR / Syphilis IgG Antibody with Reflex, Serum.

Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values


Day(s) and Time(s) Performed

Monday through Saturday; 8 a.m.

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
RPRT RPR, Response to Therapy, S 31147-2


Result ID Test Result Name Result LOINC Value
31696 RPR, Response to Therapy, S 31147-2

Clinical Information

Syphilis is a disease caused by infection with the spirochete Treponema pallidum. The infection is systemic and the disease is characterized by periods of latency. These features, together with the fact that T pallidum cannot be isolated in culture, mean that serologic techniques play a major role in the diagnosis and follow-up of treatment for syphilis.


Patients with primary or secondary syphilis should be reexamined clinically and serologically 6 months and 12 months following treatment. Typically, rapid plasma reagin titers decrease following successful treatment, but this may occur over a period of months to years.


Treatment response is generally indicated by a 4-fold (2-tube dilution) reduction in rapid plasma reagin (RPR) titer (eg, from 1:32 to 1:8). For proper interpretation of RPR results, titers should be obtained using the same testing method and, preferably, at the same testing laboratory.


Failure of nontreponemal test titers to decline 4-fold within 6 months after therapy for primary or secondary syphilis may be indicative of treatment failure. Patients whose titers remain serofast should be reevaluated for HIV infection.

Clinical Reference

1. Workowski KA, Berman S: Sexually transmitted diseases treatment guidelines. MMWR Morb Mortal Weekly Rep 2006 Aug 4;(55);22-30

2. Miller JN: Value and limitations of nontreponemal and treponemal tests in the laboratory diagnosis of syphilis. Clin Obstet Gynecol 1975 Mar 18;18(1);191-203

Analytic Time

Same day/1 day

Reject Due To


Mild OK; Gross reject


Mild OK; Gross reject





Method Name


Secondary ID


Reflex Tests

Test ID Reporting Name Available Separately Always Performed
RRPRQ RPR Titer, S No No

Testing Algorithm

If this test is positive, RPR titer will be performed at an additional charge.