Lab Test

Syphilis Total Antibody with Reflex

Syphilis Antibody, RPR, TP-PA, Treponema pallidum antibody

Test Codes



Special Chemistry

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 2.0 mL)

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8°C or 36-46°F)

Rejection Criteria

CSF or plasma specimens.
Severely lipemic or hemolyzed specimens.

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Room temperature is acceptable for a maximum of two hours. (Minimum Serum: 0.5 mL)


Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 1 year

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory


Sunday – Saturday
Results available within 24 hours of receipt in the Laboratory. 

Reference Range


Test Methodology

Syphilis Reverse Algorithm Testing Cascade



Interpretation of syphilis reverse algorithm test results:
Test results are not released to the medical record until all necessary testing is completed. 

Total Antibody   RPR  TP-PA   Interpretation
 Nonreactive  Not Performed  Not Performed  No serological evidence of syphilis  
 Reactive Reactive  Not Performed

 One of the following:
 • Active syphilis (any stage)
 • Active syphilis undergoing treatment
 • Serofast state: Persistently reactive RPR test despite adequate treatment, generally at a low titer (e.g. 1:8).  

 Reactive  Nonreactive  Reactive  One of the following:
 • Previously treated syphilis
 • Late stage syphilis  
 Reactive  Nonreactive  Nonreactive  False-positive Total Antibody screen.
 No significant serological evidence of syphilis. 

Clinical Utility

The reverse algorithm for syphilis testing at Beaumont employs the use of an automated immunoassay platform to detect IgG and IgM antibody (i.e. total antibody) against Treponema pallidum, the causative agent of syphilis. Specimens that are nonreactive for Syphilis Total Antibody demonstrate no serological evidence of a past syphilis infection (i.e. syphilis screen negative). Specimens that test reactive for syphilis total antibody are automatically reflexed to RPR (Rapid Plasma Reagin) testing. Lastly, if the Syphilis Total Antibody and RPR results are discordant (i.e. syphilis total antibody, reactive, RPR nonreactive), the specimen is tested by TP-PA (Treponema pallidum particle agglutination) to adjudicate the discordant results.

Clinical Disease

Syphilis is most commonly transmitted by sexual contact or by passage through the placenta (congenital syphilis).

Primary Syphilis:
Following acquisition of T. pallidum, the initial clinical manifestation of infection is a localized skin lesion termed a chancre. The median incubation period before the chancre appears is 21 days. Primary syphilitic lesions usually develop on the genitalia. These chancres heal spontaneously with 3-6 weeks even in the absence of antibiotic treatment.

Secondary Syphilis: Within weeks to a few months after the chancre develops, approximately 25% of individuals with untreated infection develop a systemic illness that represents secondary syphilis. Similar to the primary disease, the acute manifestation of secondary syphilis typically resolves spontaneously, even in the absence of therapy.  Patients may develop systemic symptoms including fever, headache, malaise and myalgias. Most individuals will also develop lymphadenopathy. Lastly, patients with secondary syphilis can present with dermatologic, gastrointestinal, musculoskeletal and neurologic/ocular findings.

Late Syphilis:
Approximately 25-40% of patients with untreated syphilis can develop late disease. The clinical events may appear at any time from 1-30 years after primary infection. It is not necessary for individuals to have experienced clinical symptomatic primary or secondary syphilis prior to developing late syphilis. The most common manifestations include cardiovascular syphilis (aortitis), gummatous syphilis (granulomatous nodular lesions) and central nervous system involvement. Tertiary syphilis describes patients with late syphilis who have symptomatic manifestations involving the cardiovascular system or gummatous disease.

Latent Syphilis (Asymptomatic):
Refers to the period when a patient is infected with T. pallidum, as demonstrated by serologic testing, but has no symptoms. Latent syphilis can be categorized as early latent syphilis if the infection occurred with the previous 12 months, or late latent syphilis if the infection occurred after 12 months. Only patients with early latent syphilis are considered infectious.

Disease Reporting

This is a reportable infection.  Syphilis reverse algorithm test result scenarios reported to the Michigan Department of Health and Human Services (MDHHS) are indicated below.  For more information on reportable diseases, contact the Beaumont Epidemiology Department at 248-551-4040.

Result scenarios reported to MDHHS
 Test  Scenario #1      Scenario #2    
 Syphilis Total Antibody    Reactive Reactive
 RPR   Reactive  Nonreactive
 TP-PA   Not Performed   Reactive



UpToDate – Syphilis: Epidemiology, pathophysiology, and clinical manifestations in patients without HIV, 2022.

CPT Codes


 Test  CPT Code   CPT Code Description
 Syphilis Total Antibody  86780  Treponema pallidum antibody 
 RPR Screen 86592  Syphilis test, non-treponemal antibody; qualitative
 RPR Titer 86593  Syphilis test, non-treponemal antibody; quantitative 
 TP-PA 86780  Treponema pallidum antibody



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