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Test Code RPRB Rapid Plasma Reagin (RPR), Infant,  Serum

Important Note

As an initial screening order, this test code is only available for patients <6 months of age.

Patients over 6 months of age will be converted to Syphilis Antibody.  Please see Bronson test ID SYPHG for additional test information.

The RPR test is performed on patients >6 months as reflex testing for positive Syphilis Antibody samples.  In addition for monitoring of patients under treatment, the test code RPRTX is used.

Additional Codes

Epic LAB3359

Test Usage

RPR testing is no longer the first line of testing at Bronson for syphilis screening. The RPR will be performed as a confirmatory, second screening test to the Syphilis Total antibody test, when that antibody is positive.

If an order request for RPR is placed, the order will be updated to Syphilis IgG.  

 

In some patients, the results of the treponemal screening test (syphilis IgG) and RPR may be discordant (e.g., syphilis IgG positive and RPR negative). To discriminate between a falsely reactive screening result and past syphilis, CDC recommends performing a second treponemal-specific antibody test using a method that is different from the initial screen test (eg, Treponema pallidum particle agglutination: TP-PA).  At Bronson, this test is sent to the Michigan Dept of Public Health.

 

In the setting of a positive syphilis IgG screening result and a negative RPR, a positive TP-PA result is consistent with either 1) past, successfully treated syphilis, 2) early syphilis with undetectable RPR titers, or 3) late/latent syphilis in patients who do not have a history of treatment for syphilis. Further historical evaluation is necessary to distinguish between these scenarios.

 

In the setting of a positive syphilis IgG screening result and a negative RPR, a negative TP-PA result is most consistent with a falsely reactive syphilis IgG screen.  If syphilis remains clinically suspected, a second specimen should be submitted for testing.

 

In the setting of a positive syphilis IgG screening resultm a postiive RPR,  and a negative TP-PA result is most consistent with a falsely reactive syphilis IgG and RPR test due to immunoassay interfering antibodies.  If syphilis remains clinically suspected, a second specimen should be submitted for testing.

 

 

Reference Values

Nonreactive

 

Note: Reactive results will automatically include a titer value.

Methodology

Multiplex flow immunoassay

Please see the January 2019 LabWire at the link under the "Resources" section of this page for information on the Methodology change.

 

 

Specimen Requirements

Specimen Type: Serum

Container/Tube: Gold-top serum gel-Red-top tube
is also acceptable.

Specimen Volume: 5 mL

Specimen Minimum Volume: 1.5 mL

Specimen Transport Temperature

Refrigerate

Day(s) Test Set Up

Monday through Friday, Day shift

Test Classification and CPT Coding

RPR Test:  86592

RPR Titer (if performed) 86593