Coccidioidomycosis (Valley Fever)

Lab Tests

Confirmation of coccidioidomycosis requires the demonstrated presence of Coccidioides by histopathologic, cultural or molecular means and/or demonstration of a specific immunologic response: skin test conversion or demonstration of presence of coccidioidal antibody. The results of these immunologic tests must be interpreted in the context of the varied clinical presentations and duration and clinical type of coccidioidomycosis.

Lab Criteria for Diagnosis

Laboratory-confirmed coccidioidomycosis requires at least one of the following:

• Cultural, histopathologic, or molecular evidence of presence of Coccidioides species, OR
• Immunologic evidence of infection
  • Serologic (testing of serum, cerebrospinal fluid (CSF), or other body fluid) by:
    • Detection of coccidioidal IgM by immunodiffusion, enzyme immunoassay (EIA), latex agglutination, or tube precipitin, OR
    • Detection of coccidioidal IgG by immunodiffusion, enzyme immunoassay (EIA), or complement fixation (for complement fixation, titers from blood must be = 1:4; for immunodiffusion or when the specimen is CSF, any titer is considered positive).
  • Coccidioidal skin test conversion from negative to positive after the onset of clinical signs and symptoms.