Test Catalog

Test Id : RRPRS

Rapid Plasma Reagin Screen with Reflex to Titer, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aid for the diagnosis of infection with Treponema pallidum

 

Rapid plasma reagin testing following a positive treponemal antibody test

 

This test is not useful as a screening or confirmatory test for blood donor specimens.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the rapid plasma reagin (RPR) screen is positive, then the RPR titer will be performed at an additional charge.

 

If the RPR screen is negative, then syphilis antibody Treponema pallidum particle agglutination testing will be performed at an additional charge.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Only orderable as a reflex. For more information see Syphilis IgG with Reflex, Enzyme Immunoassay, Serum.

 

Flocculation/Agglutination

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

RPR Screen w/ Reflex to Titer, S

Aliases
Lists additional common names for a test, as an aid in searching

Rapid Plasma Reagin (RPR)

RPR (Rapid Plasma Reagin)

Syphilis G, Serum

Syphilis Serology (RPR)

T. pallidum (Treponema pallidum)

Treponema pallidum (T. pallidum)

RRPRS

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the rapid plasma reagin (RPR) screen is positive, then the RPR titer will be performed at an additional charge.

 

If the RPR screen is negative, then syphilis antibody Treponema pallidum particle agglutination testing will be performed at an additional charge.

Specimen Type
Describes the specimen type validated for testing

Serum

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Only orderable as a reflex. For more information see SYPH1 / Syphilis IgG with Reflex, Enzyme Immunoassay, Serum

 

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Information: Centrifuge and aliquot serum into plastic vial.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.4 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

No specimen should be rejected.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 14 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aid for the diagnosis of infection with Treponema pallidum

 

Rapid plasma reagin testing following a positive treponemal antibody test

 

This test is not useful as a screening or confirmatory test for blood donor specimens.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the rapid plasma reagin (RPR) screen is positive, then the RPR titer will be performed at an additional charge.

 

If the RPR screen is negative, then syphilis antibody Treponema pallidum particle agglutination testing will be performed at an additional charge.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Syphilis is caused by infection with the spirochete Treponema pallidum subspecies 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.

 

Historically, the serologic testing algorithm for syphilis included an initial nontreponemal screening test, such as the rapid plasma reagin (RPR) or the VDRL tests. Because these tests measure the host's immune response to nontreponemal antigens, they lack specificity. Therefore, a positive result by RPR or VDRL requires confirmation by a treponemal-specific test, such as the fluorescent treponemal antibody-absorption (FTA-ABS) or microhemagglutination (MHA-TP) assay. Although the FTA-ABS and MHA-TP assays are technically simple to perform, they are labor intensive and require subjective interpretation by testing personnel.

 

As an alternative to the traditional syphilis screening algorithm, many laboratories utilize the reverse syphilis screening algorithm. This algorithm starts with an automated treponemal assay to detect antibodies specific to T pallidum. If this screening assay is positive, the sample is reflexed for testing by RPR, which, if positive, is reported with a titer and is indicative of active or recent syphilis infection. If the RPR is negative, the sample is reflexed to a second treponemal assay, such as the T pallidum particle agglutination (TP-PA) assay. If the TP-PA is positive, this would indicate previously treated or late-stage syphilis infection. Alternatively, if the TP-PA is negative, the initial positive screen is interpreted as a false-positive result.

 

Syphilis screening at Mayo Clinic is performed using the reverse algorithm, which first tests sera for T pallidum specific IgG antibodies using an automated enzyme immunoassay. A positive treponemal test suggests infection with T pallidum but does not distinguish between recent, past, treated, or untreated infections. This is because treponemal tests may remain reactive for life, even following adequate therapy. Therefore, the results of a nontreponemal assay, such as RPR, are needed to provide information on a patient's disease state and history of therapy.(Table)

 

In some patients, the results of the treponemal screening test and RPR may be discordant (eg, syphilis IgG positive and RPR negative). To discriminate between a falsely reactive screening result and past syphilis, a second treponemal-specific antibody test is recommended using a method that is different from the initial screen test (eg, TP-PA).

 

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, 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.(Table)

 

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.(Table) If syphilis remains clinically suspected, a second specimen should be submitted for testing.

 

Table. Interpretation and follow-up of reverse screening results:

 

Test and result

Patient history

Syphilis IgG antibody by EIA

RPR

TP-PA

Interpretation

Follow-up

Unknown history of syphilis

Nonreactive

NA

NA

No serologic evidence of syphilis

None, unless clinically indicated (eg, early/acute/ primary syphilis)

Unknown history of syphilis

Reactive

Reactive

NA

Untreated or recently treated syphilis

See Centers for Disease Control and Prevention treatment guidelines

Unknown history of syphilis

Reactive

Nonreactive

Nonreactive

Probable false-positive screening test

No follow-up testing, unless clinically indicated (eg, acute/ primary syphilis)

Unknown history of syphilis

Reactive

Nonreactive

Reactive

Possible syphilis (eg, early or latent) or previously treated syphilis

Historical and clinical evaluation required

Unknown history of syphilis

Equivocal

NA

NA

NA

Unknown history of syphilis

Known history of syphilis

Reactive

Nonreactive

Reactive or NA

Past, successfully treated syphilis

None

EIA-enzyme immunoassay

NA-not applicable

RPR-rapid plasma reagin

TP-PA-T pallidum particle agglutination

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Only orderable as a reflex. For more information see Syphilis IgG with Reflex, Enzyme Immunoassay, Serum.

 

Negative

Reference values apply to all ages

Interpretation
Provides information to assist in interpretation of the test results

Negative:

Treponema pallidum-particle agglutination has been ordered to distinguish between infection with T pallidum (syphilis) versus a falsely reactive treponemal antibody result.

 

Positive:

Specimen reflexed to determine rapid plasma reagin titer value.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Despite active syphilis, serologic tests may be negative in severely immunosuppressed patients such as those with AIDS.

 

In very early cases of primary syphilis, serology tests for syphilis may be negative.

 

In cases of untreated, late or latent syphilis, the result of rapid plasma reagin may be negative. However, the syphilis screening using a treponemal assay, including the Treponema pallidum particle agglutination test, should be positive. A thorough clinical and historical evaluation should be performed to determine if treatment for latent syphilis is required.

 

Results should be considered in the context of all available clinical and laboratory data.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Centers for Disease Control and Prevention (CDC): Discordant results from reverse sequence syphilis screening-five laboratories, United States, 2006-2010. MMWR Morb Mortal Wkly Rep. 2011 Feb 11;60(5):133-137

2. Radolf JD, Tramont EC, Salazar JC: Syphilis (Treponema pallidum). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2865-2892

3. Binnicker MJ, Jespersen DJ, Rollins LO: Direct comparison of the traditional and reverse syphilis screening algorithms in a population with a low prevalence of syphilis. J Clin Microbiol. 2012 Jan;50(1):148-150. doi: 10.1128/JCM.05636-11

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

If the IgG result is equivocal or reactive, a rapid plasma reagin (RPR) screen is performed manually. If the RPR screen is positive the RPR titer is performed manually. The RPR titer test is a macroscopic screening assay done with unheated serum. Reagin reacts with nontreponemal antigen containing colloidal charcoal particles. This reaction results in a visual flocculation of the black particles against the white card background. The test yields a positive or negative result, and all positive samples are titered to determine the highest positive dilution.(Huber TW, Storms S, Young P, et al: Reactivity of microhemagglutination, fluorescent treponemal antibody absorption, Venereal Disease Research Laboratory, and rapid plasma reagin tests in primary syphilis. J Clin Microbiol. 1983 Mar;17[3]:405-409; Kaur G, Kaur P: Syphilis testing in blood donors: an update. Blood Transfus. 2015 Apr;13[2]:197-204)

 

If the RPR screen is negative, the Serodia Treponema pallidum particle agglutination (TP-PA) test is performed. The TP-PA test is based on the agglutination of colored gelatin particle carriers sensitized with T pallidum (Nichols Strain) antigen. Serum samples are serially diluted in microplate wells. Sensitized gelatin particles are added to respective wells and the contents of the plate mixed. The mixture is incubated for 2 hours at ambient temperature. Serum containing specific antibodies will react with the antigen-sensitized colored gelatin particles to form a smooth mat of agglutinated particles in the microplate well. A compact button formed by the settling of the non-agglutinated particles characterizes negative reactions. The agglutination patterns are read visually to determine interpretation.(Package insert: Serodia TP-PA. Fujirebio Diagnostics, Inc; 04/2015)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Saturday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 2 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US 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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

86592-Rapid Plasma Reagin Screen

86593-Rapid Plasma Reagin Titer (if appropriate)

86780-Syphilis Antibody by TP-PA (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
RRPRS RPR Screen w/ Reflex to Titer, S 47238-1
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
616866 RPR Screen w/ Reflex to Titer, S 47238-1

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

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Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports