CaptiaTM Syphilis IgG EIA

Syphilis IgG EIA

  • Laboratory Location – Central Laboratory
  • CPT Code – 86318
  • Synonyms – Syph G, Syphilis, Treponema pallidum, Treponema, Syphilis IgG
  • Test Description - CaptiaTM Syphilis IgG is an enzyme immunoassay for the qualitative detection of IgG antibodies in serum to Treponema pallidum, the agent of syphilis. This test is to be used in conjunction with non-trepnemal testing to provide serological evidence of infection with Treponema pallidum.

Possible Results

  • Non-Reactive
  • Equivocal
  • Reactive

Reference Range

  • Non-Reactive

Specimen Requirements

  • Specimen Type - Serum
  • Specimen Container(s) - red top tubes, Marble top tubes, polypropylene vials
  • Minumum accepted volume - 210 μL (does not allow for repeat testing)

Specimen Collection Instructions

Blood should be collected in a plastic, sterile STD Program approved collection tube. Please follow the manufacturer's instructions on clot time and centrifuge speed/time requirements.

The Syphilis Serology Lab 16 form must be filled out completely. The following information must be included on the form:

  • Patient's Name
  • Patient's Date of Birth
  • Patient's Gender
  • Patient's race/ethnicity
  • Date and time of specimen collection
  • Test requested
  • Type of specimen collected
  • Submitter's name and address

Storage and Transport Instructions

Speciments should be shipped refrigerated (2-8ºC). Specimens can be stored for up to 5 days at 2-8ºC. For longer storage, specimens must be frozen at -10ºC or colder. Frozen specimens must be shipped on dry ice and received at a temperature of -10ºC or colder.

Causes for Rejection

  • Hemolyzed, lipemic, or icteric specimens must be rejected.
  • Improper labeling,
  • expired collection tubes
  • unspun samples
  • tubes that contain less than 90% of the total drawing capacity (QNS)
  • Specimen age greater than 5 days if specimen has not been frozen at -20ºC or colder
  • Improper storage or improper temperature requirements are also reasons for rejection

Limitations for the Procedure

Results from the Syphilis IgG EIA should be considered in the context of all available clinical and laboratory data. A non-reactive result does not preclude the possibility of a very recent infection (within the last 2-3 weeks) or an old successfully cured infection (for examples > 10 years previous). Syphilis IgG EIA may be reactive with sera from patients with Yaws or Pinta. Detection of treponemal antibodies may indicate recent, past, or successfully treated syphilis infection, therefore, the test cannot be used to differentiate between active and cured cases. Any sera giving reactive or equivocal results must be supplemented with a quantitative non treponemal test (such as RPR or VDRL) to distinguish active disease and assist in ruling out false positive. The Syphilis IgG EIA is a treponemal assay; therefore patients with previously treated syphilis will be positive on the assay. AIDS patients with impaired immunity and who are coinfected with syphilis may react falsely nonreactive in treponemal and nontreponemal tests. Reactive treponemal IgG antibody tests usually remain reactive for a lifetime; therefore the presence of antibody cannot be used to determine response to therapy.

Interfering Substances

  • Grossly hemolyzed, lipemic or icteric specimens


  • CaptiaTM Syphilis IgG EIA package insert
  • EVOLISTM Operator Manual


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