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Test Code LAB5333 SYPHILIS TOTAL ANTIBODY W/REFLEX TO RPR SCREEN

Important Note

Reactive results are reflexed to a Rapid Plasma Reagin (RPR) screen. Reactive RPR results will reflex further to a RPR titer.  Non-reactive RPR results will reflex to a second treponemal Syphilis TP-PA antibody test. This test is performed at Mayo Clinic.

Additional Codes

Labcorp 082345 or 012005

Interpath 1003

Specimen Type

Preferred: Serum (SST, Gold, Corvac, Tiger, Red Top Tube)

Alternate: Lithium Heparin (Light Green/Dark Green top tube)

Note: The TPPA test requires Serum, if the TPPA reflex is needed, Lithium heparin samples will require recollection.

Specimen Volume

1 mL

Minimum Volume

0.5 mL

Turnaround Time

STAT: 2 hours
Routine: 4 hours

Test Schedule

Daily

Sample Stability

Room Temperature: 3 days

Refrigerated: 7 days

Frozen: 30 days

Method

Chemiluminescent microparticles immunoassay (CMIA)

Reference Ranges

Nonreactive

Analyte Non Reactive Reactive
SYPHILIS TOTAL ANTIBODY <1.00 > 1.00

Synonyms

Syphilis

Treponema pallidum

Syphilis antibodies, syphilis IgG, syphilis IgG IgM IgA,

Syphilis IgG Antibody w/Reflex to RPR Screen

treponema pallidum (syphilis) screening cascade

CPT Codes

86780

Specimen Rejection

Do not use lipemic, hemolyzed, or turbid specimens.

Interpretation

Treponemal Result Alinity i Syphilis TP

Non-Treponemal Result (NT)

Report/interpretation for all except neonates or infants.2

Positive (reactive) 

S/CO ≥ 1.00

Nonreactive

Probably past infection or potential cross-reactivity with other spirochetes/related antigens; additional testing appropriate to clinical findings/history;1 possibility of false negative non-treponemal (NT) due to prozone and late syphilis or neurosyphilis.

Positive (reactive) 

S/CO ≥ 1.00

Reactive

Presumptive evidence of current infection (or inadequately treated infection, persistent infection, reinfection, or biological false positive if prior history); additional testing consistent with clinical assessment.1

Negative (nonreactive)

S/CO <1.00

Not done

Current or past infection unlikely; cannot exclude incubating or early syphilis.2

1 Quantitative non-treponemal testing; clinical history; repeated (sequential) serological testing for changes in titer. 2 HIV-infected individuals may have delayed seroreactivity or negative serology.

Limitations

  • A non-reactive result does not preclude the possibility of:
        (a) a very recent infection (within the last 2-3 weeks) with T.pallidum. (b) an old, successfully cured infection with T. pallidum (for example >10 years previous).
  • Alinity i Syphilis TP assay may be reactive with sera from patients with Yaws (T. pallidum subspecies pertenue) or Pinta (T. carateum).
  • Detection of treponemal antibodies may indicate recent, past, or successfully treated syphilis infections, therefore, the test cannot be used to differentiate between active and cured cases.

Clinical Information

Syphilis is an infection that is primarily transmitted through sexual contact or congenitally. It is caused by the bacterium Treponema pallidum (TP). The infection is systemic and has four different clinically defined stages which include primary, secondary, latent and tertiary. The latent stage is asymptomatic and can last in excess of twenty years. Infection with TP results in an immune response to not only antigens specific to TP but also to antigens released during cellular damage caused by the bacterium.

 

To aid in the diagnosis of syphilis, two types of tests have been developed. Treponemal tests indicate an acute, latent, or past infection. Nontreponemal tests aid in the monitoring of disease activity and in therapy response. The Alinity i Syphilis assay is a treponemal assay that detects IgG and IgM antibodies to TP. Reactive treponemal tests should be confirmed with a nontreponemal supplementary test like a Rapid Plasma Reagin (RPR).