Clinical Laboratory Utility of a Humanized Antibody in Commercially Available Enzyme Immunoassays for Coccidioidomycosis

Francisca J. Grill, Collin Jugler, Erin Kaleta, Qiang Chen, D. Mitchell Magee, Thomas E. Grys, Douglas F. Lake

Research output: Contribution to journalArticlepeer-review


Coccidioidomycosis, also called valley fever (VF), is a fungal infection with endemicity in desert regions of the western United States as well as certain arid regions of Central and South America. Laboratory-based diagnosis of VF often relies on the composite results from three serologic-based diagnostics, complement fixation, immunodiffusion, and enzyme immunoassay (EIA). EIA is commonly performed in clinical laboratories because results can be obtained in a few hours. Two commercially available EIAs, IMMY clarus Coccidioides antibody and Meridian Premier Coccidioides, look for the presence of anticoccidioidal IgG and IgM in patient sera that are diluted 1:441. Per regulatory requirements, this dilution step must be verified with a dilution step control despite not being provided as a reagent in either FDA-approved EIA kit. Therefore, clinical laboratories collect and reuse patient sera in subsequent tests that had a positive result in a previous test. This is a nonstandard process, reinforcing the need for a consistent and reliable dilution control. Here, we evaluate the performance of a humanized IgG and IgM antibody as a dilution control in both EIA kits. Both humanized IgG and IgM work well in each EIA and meet the appropriate threshold for positivity.

Original languageEnglish (US)
JournalMicrobiology Spectrum
Issue number5
StatePublished - Sep 2022


  • CLIA
  • coccidioidomycosis
  • diagnostic
  • enzyme immunoassay
  • monoclonal antibodies

ASJC Scopus subject areas

  • Physiology
  • Ecology
  • General Immunology and Microbiology
  • Genetics
  • Microbiology (medical)
  • Cell Biology
  • Infectious Diseases


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