Test Id : RPRS
Rapid Plasma Reagin Screen with Reflex, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Aiding in the diagnosis of recent or past Treponema pallidum infection
Rapid plasma reagin screening when T pallidum antibody screen is positive
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 reactive, then the RPR titer will be performed at an additional charge.
If the RPR screen is nonreactive, then syphilis antibody Treponema pallidum particle agglutination testing will be performed at an additional charge.
Method Name
A short description of the method used to perform the test
Only available as a reflex test. For more information, see SYPHT / Syphilis Total Antibody with Reflex, Serum.
RPRS: Multiplex Flow Immunoassay
RRPRQ: Flocculation/Agglutination
RTPPA: Particle Agglutination
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
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)
ART (Automated Reagin Test)
Automated Reagin Test (ART)
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 reactive, then the RPR titer will be performed at an additional charge.
If the RPR screen is nonreactive, 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 available as a reflex test. For more information see SYPHT / Syphilis Total Antibody with Reflex, 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. The minimum volume is sufficient for one attempt at testing.
0.4 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Heat-inactivated specimen | Reject |
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 | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Aiding in the diagnosis of recent or past Treponema pallidum infection
Rapid plasma reagin screening when T pallidum antibody screen is positive
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 reactive, then the RPR titer will be performed at an additional charge.
If the RPR screen is nonreactive, 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 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.
Historically, the serologic testing algorithm for syphilis included an initial non-treponemal screening test, such as the rapid plasma reagin (RPR) or VDRL tests. Because these tests measure the host's antibody response to non-treponemal 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-absorbed (FTA-ABS) or microhemagglutination assay (MHA-TP). Although the FTA-ABS and MHA-TP 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 as described above, many laboratories utilize the reverse syphilis screening algorithm. This algorithm starts with an automated treponemal assay, such as an enzyme immunoassay and multiplex flow immunoassay (MFI), to detect antibodies specific to T pallidum. If the screening assay is positive, the sample is reflexed to a RPR assay, 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 by using the reverse algorithm, which first tests sera for T pallidum specific IgG/IgM antibodies using an automated MFI. A positive treponemal test suggests infection with T pallidum, but does not distinguish between recent or past, or treated and untreated infection. This is because treponemal tests may remain reactive for life, even following adequate therapy. Therefore, the results of a non-treponemal assay, such as RPR, are needed to provide information on a patient's disease state and history of therapy.(Table 1)
In some patients, the results of the treponemal screening test and RPR may be discordant (eg, syphilis IgG/IgM 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/IgM 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.(Table 1)
In the setting of a positive syphilis IgG/IgM screening result and a negative RPR, a negative TP-PA result is most consistent with a falsely reactive syphilis IgG/IgM screen.(Table 1) If syphilis remains clinically suspected, a second specimen should be submitted for testing.
Table 1. Interpretation and follow-up of reverse screening results:
| Test and result | |||||
| Patient history | Syphilis total antibody by MFI | 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 CDC 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 |
| MFI - multiplex flow immunoassay NA - not applicable RPR - rapid plasma reagin TP-PA - Treponema 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 available as a reflex test. For more information see SYPHT / Syphilis Total Antibody with Reflex, Serum.
Nonreactive
Interpretation
Provides information to assist in interpretation of the test results
Nonreactive:
Treponema pallidum-particle agglutination (TP-PA) has been ordered to distinguish between infection with T pallidum (syphilis) versus a falsely reactive treponemal antibody result
Reactive:
Specimen reflexed to determine rapid plasma reagin (RPR) 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 test multiplex flow immunoassay and Treponema pallidum particle agglutination 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;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
Method Description
Describes how the test is performed and provides a method-specific reference
The BioPlex 2200 Syphilis Total and RPR kit employs Treponema pallidum fusion protein (rTP47/rTP17) and cardiolipin antigen-coated fluoromagnetic beads with unique fluorescent signatures to identify the presence of IgG and IgM antibodies to T pallidum and nontreponemal reagin antibodies in a 2-step assay format. Dyed beads are coated with recombinant T pallidum rTP47/rTP17 fusion protein or cardiolipin antigen. The BioPlex 2200 System combines an aliquot of patient sample, sample diluent, and bead reagent into a reaction vessel. The mixture is incubated at 37 degrees C. After a wash cycle, a mixture of murine monoclonal anti-human IgG and murine monoclonal anti-human IgM antibody conjugated to phycoerythrin (PE) is added to the dyed beads, and this mixture is incubated at 37 degrees C. The excess conjugate is removed in another wash cycle, and the beads are re-suspended in wash buffer. The bead mixture then passes through the detector. The identity of the dyed beads is determined by the fluorescence of the dyes, and the amount of antibody captured by the antigen is determined by the fluorescence of the attached PE. Raw data is calculated in relative fluorescence intensity (RFI).(Package insert: BioPlex 2200 Syphilis Total and RPR. Bio-Rad; 06/2017)
If the total antibody result is reactive, a rapid plasma reagin (RPR) screen is performed on the BioPlex 2200. If the RPR screen is reactive the RPR titer is performed. 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
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.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
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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.
CPT codes are provided by the performing laboratory.
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 |
|---|---|---|
| RPRS | RPR Screen w/ Reflex, S | 20507-0 |
| 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.
|
|---|---|---|
| RPRS | RPR Screen w/ Reflex, S | 20507-0 |