Test Overview
Test Methodology

Nontreponemal flocculation procedure (RPR).

Test Usage

Screening test for syphilis.

Reference Range *


* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Nonspecific positive reactions may be found in SLE, malaria, infectious mononucleosis, hepatitis, leprosy, brucellosis, atypical pneumonia, typhus, and other infections. Reactive tests due to related treponemal infections (bejel, pinta, or yaws) may also occur. A reactive result in a newborn may be due to passive transfer from mother's blood.

Test Details
Days Set Up
Monday - Friday
Analytic Time

8 hours

Soft Order Code
  • Rapid Plasma Reagin
  • Rapid Plasma Reagin, Serum
  • RPR, Serum
  • Serologic Test for Syphilis
  • STS
  • Syphilis Antibody Screen
  • Syphilis Screening Test
  • Treponema pallidum Antibody Screen, Serum
  • VDRL Equivalent, Serum
  • Rapid Plasma Reagin
  • Serologic Test for Syphilis
  • STS
  • Syphilis Screening Test
  • VDRL Equivalent, Serum
  • RPR
Chemical Pathology
Specimen Requirements
Collection Instructions

Collect specimen in SST tube. Centrifuge, aliquot serum into plastic vial and refrigerate.
Contaminated, lipemic or grossly hemolyzed sera should not be used because of the possibility of nonspecific reactions.

Alternate Specimen
Red top tube.
Plasma, EDTA, heparin or sodium citrate.
Normal Volume
0.5 ml serum
Minimum Volume
0.5 ml serum
Rejection Criteria
Additional Information

Reactive specimens will be titered (RPRQN) and the more specific TPPA test will be performed for confirmation at additional charges. By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated. In untreated syphilis, reactive sera are found in the chancre stage 30% after one week and 90% after three weeks. In the secondary stage, the RPR should be reactive 100% of the time, decreasing to 90% in the tertiary stage. In the latent stage and after successful treatment, the RPR may become nonreactive. The titer of antibody will vary from patient to patient. There is no direct relationship between the amount of reagin and the severity of disease. A patient's peak titer will usually occur during the secondary stage, then decrease and plateau during later stages.

CPT Code
Fee Code
Reflex CPT
86593 Titer, 86780 TPPA
Reflex Fee Code
21923 RPRQN, KA050 TPPA
20507-0 (RPR), 31147-2 (RPRQN)