Comparison of two immunoassay procedures for detecting enterovirus IgM

Area of Science:

• Virology
• Immunology
• Diagnostic Assays

Background:

• Enteroviruses cause significant human illness, yet their diagnosis presents challenges.
• Enterovirus-specific IgM tests exist but lack reliable control sera, leading to arbitrary data interpretation.
• Assessing the reliability of these diagnostic assays is crucial for accurate patient management.

Purpose of the Study:

• To evaluate the reliability of enterovirus-specific IgM assays by comparing two independent tests.
• To assess the concordance and discrepancies between a mu-capture radioimmunoassay (MACRIA) and an enzyme immunoassay (EIA).
• To identify challenges in interpreting serological data for enteroviral infection diagnosis.

Main Methods:

• Comparison of a mu-capture radioimmunoassay (MACRIA) using 35S-labelled Coxsackie virus antigens with a routine enzyme immunoassay (EIA).
• Independent testing of 120 patient sera in two different laboratories.
• Analysis of concordance rates and discrepant results between the MACRIA and EIA, including testing against individual Coxsackie B1-5 serotypes.

Main Results:

• An overall concordance of 85% was achieved when testing 120 sera between the MACRIA and EIA.
• Discrepant results were observed in 18 sera (11 positive by EIA only, 7 by MACRIA only).
• High concordance (89-95%) was found when testing against individual Coxsackie B serotypes, with some MACRIA results suggesting type specificity.

Conclusions:

• While MACRIA is suitable for research, EIA is more practical for routine diagnostics.
• Qualitative differences between assays and the absence of a gold standard complicate serological data interpretation for enteroviral infections.
• Sole reliance on serology for diagnosing enteroviral infections is cautioned against due to interpretation challenges.