Antibody Detection


  • Test Code


  • CPT Code

    86635 x2

  • Clinical Significance
    IgM and IgG antibodies to Coccidioides antigen usually appear during the first month of infection, decline over the next 3-6 months but remain detectable for approximately 18-24 months in some cases with self-limited illnesses. Antibodies may persist in patients with chronic pulmonary complications or progressive extrapulmonary (disseminated) coccidioidomycosis. Antibodies may be falsely-negative in some progressive or chronic cases. Follow-up testing maybe considered at weeks 2 – 4 to determine if antibody levels are increasing especially in patients with low positive (10 EU – 20 EU) or intermediate results. Increase in antibody concentration would suggest recent infection. Antibodies may also be detected in healthy subjects who are asymptomatic as a result of sub-clinical infection within the last 18 – 36 months.
  • Methodology
    Semi-Quantitative Indirect Enzyme Immunoassay (EIA)
  • Limitations
    • 8% cross reactivity with Blastomycosis
    • 36% cross reactivity with Histoplasmosis
  • Specimen Collection

    Serum: Collect serum specimens in serum separator or red top tube. Allow blood to clot for 30 minutes, then centrifuge. Pipette serum into a plastic screw cap vial.

    CSF: Sterile transport tube

  • Minimum Specimen Requirements

    Serum/CSF: 0.5 mL

  • Specimen Stability
    • Refrigerated: 14 days
    • Frozen: 14 days
  • Specimen Rejection

    Any specimen types other than serum or cerebrospinal fluid (CSF)

  • Transport Temperature


  • Shipping

    Ship on dry ice to arrive Monday‐Friday using a next day delivery service. Frozen ice packs may be substituted if sample is shipped the day of collection.

  • Turnaround Time

    Testing performed Mondays and Thursdays.

    Serum or CSF: TAT reported next day

  • Reference Range


  • Interpretative Information
    • Negative: <8.0 EU
    • Intermediate: 8.0 EU – 9.9 EU
    • Positive: 10.0 EU – >80.0 EU
  • vendor logo
  • vendor logo
  • vendor logo
  • vendor logo
  • vendor logo