Related Experiment Video

Updated: May 13, 2026

Dynamic Monitoring of Seroconversion using a Multianalyte Immunobead Assay for Covid-19
08:48

Dynamic Monitoring of Seroconversion using a Multianalyte Immunobead Assay for Covid-19

Published on: February 16, 2022

Enyzme immunoassay compared to immunodiffusion complement-fixation to assess the IgG serological response in

Chinh T Nguyen1, Neil M Ampel1

  • 1From the Southern Arizona Veterans Affairs Health Care System (SAVAHCS) and the University of Arizona, Tucson, AZ.

Medical Mycology
|May 12, 2026
PubMed

Insights

Enzyme immunoassay (EIA) for coccidioidomycosis may yield false positives. Comparing EIA immunoglobulin G (IgG) optical density (OD) to complement-fixation (CF) titer reveals moderate correlation, suggesting EIA IgG OD is not a reliable substitute for CF titer.

Area of Science:

  • Medical diagnostics
  • Immunology
  • Infectious diseases

Background:

  • Serological tests are crucial for diagnosing coccidioidomycosis.
  • Enzyme immunoassay (EIA) immunoglobulin G (IgG) optical density (OD) is a common initial diagnostic test.
  • Immunodiffusion complement-fixation (IDCF) titer is a confirmatory serological method.

Purpose of the Study:

  • To evaluate the correlation between EIA IgG OD and IDCF titer in diagnosing coccidioidomycosis.
  • To determine the clinical significance of positive EIA IgG results when IDCF is negative.

Main Methods:

  • Comparison of EIA IgG OD results with IDCF titers in 339 unique patient samples.
  • Review of medical records for 22 patients with positive EIA IgG tests to assess clinical activity.

Main Results:

  • Moderate correlation (R2=0.5345; P <0.001) was observed between EIA IgG OD and IDCF titer.
  • In 20.1% of cases (68/339), EIA IgG was positive while IDCF was negative.
  • Only 63.6% (14/22) of patients with positive EIA IgG tests had clinically active coccidioidomycosis.

Conclusions:

  • EIA IgG OD should not be used as a substitute for CF titer in diagnosing coccidioidomycosis.
  • An isolated positive EIA IgG result may indicate a false positive, necessitating further confirmatory testing.

Keywords:
coccidioidomycosiscomplement fixationenzyme immunoassayserology

More Related Videos

Multiplexed Fluorometric ImmunoAssay Testing Methodology and Troubleshooting08:05

Multiplexed Fluorometric ImmunoAssay Testing Methodology and Troubleshooting

Published on: December 12, 2011

Simultaneous Detection of Different Antibody Classes in a Multiplexed Serological Test05:25

Simultaneous Detection of Different Antibody Classes in a Multiplexed Serological Test

Published on: July 14, 2023

Related Concept Videos

Immunocytochemistry and Immunohistochemistry01:22

Immunocytochemistry and Immunohistochemistry

Immunocytochemistry (ICC) and immunohistochemistry (IHC) are techniques that use antibodies to check for specific proteins or antigens in a sample. The technique was first published by Albert Coons in 1941 to detect the presence of pneumococcal antigen in tissue sections from mice infected with Pneumococcus. Immunocytochemistry helps localization of proteins or antigens in individual cells like blood cells, stem cells, etc., while immunohistochemistry does the same for tissue samples.
These...
Enzyme-Linked Immunosorbent Assay01:33

Enzyme-Linked Immunosorbent Assay

In 1971, Peter Perlman and Eva Engvall developed an Enzyme-linked immunosorbent assay (ELISA or EIA). ELISA differs from western blot in that the assays are conducted in microtiter plates or in vivo rather than on an absorbent membrane.
There are many different types of ELISAs, but they all involve an antibody molecule whose constant region binds an enzyme, leaving the variable region free to bind its specific antigen.  Enzyme-substrate reaction allows the antigen to be visualized or quantified.