First international proficiency study on West Nile virus molecular detection

Area of Science:

• Virology
• Molecular Diagnostics
• Public Health

Background:

• Molecular detection of West Nile virus (WNV) is increasingly performed globally.
• Variability in laboratory proficiency necessitates external quality control measures.

Purpose of the Study:

• To assess the proficiency of laboratories in WNV molecular detection through an international quality assurance study.
• To identify challenges in detecting different WNV lineages and other flaviviruses.

Main Methods:

• An international quality assurance study involving 30 laboratories.
• Distribution of coded, inactivated samples including WNV (lineages 1a, 1b, 2) at varying concentrations, heterologous flaviviruses, and negative controls.

Main Results:

• Laboratories demonstrated good WNV lineage 1 detection but significantly lower detection rates for WNV lineage 2.
• Detection probability for WNV averaged 50% from 7762 copies/mL, with only 27% detecting samples at 1.8 x 10(4) copies/mL.
• False-positive results were reported by three labs; correct non-WNV flavivirus identification was achieved by six labs.

Conclusions:

• Most laboratories excel at detecting predominant WNV lineage 1 strains.
• Underperformance in detecting WNV lineage 2 highlights a critical gap in diagnostic capabilities.
• Provided WNV lineage 2 materials can aid laboratories in assay improvement.