A Multi-Laboratory Evaluation of Commercial Monkeypox Virus Molecular Tests

Area of Science:

• Virology
• Molecular Diagnostics
• Public Health

Background:

• Monkeypox virus (MPXV) poses a significant public health threat.
• Accurate and reliable diagnostic assays are crucial for MPXV detection and control.
• Commercial PCR kits offer potential for widespread diagnostic use.

Purpose of the Study:

• To conduct the first national-scale, multi-laboratory evaluation of commercial MPXV DNA PCR kits.
• To compare the performance of two specific commercial kits (Novaplex and Bio-Speedy) against an in-house reference assay.
• To provide guidance for diagnostic laboratories in selecting appropriate MPXV detection assays.

Main Methods:

• Ten standardized samples were tested across multiple laboratories using Novaplex and Bio-Speedy kits.
• An in-house PCR assay served as the reference standard for comparison.
• Data on Cq values and relative fluorescence (RF) were collected and analyzed.

Main Results:

• All tested assays demonstrated high intra-assay agreement and sensitivity for detecting low viral loads.
• Significant differences in Cq values and relative fluorescence were observed between the commercial kits and the in-house assay.
• Novaplex showed lower RF signals, while Bio-Speedy had lower Cq values compared to the in-house assay.

Conclusions:

• Commercial MPXV PCR kits show comparable sensitivity but differ in measurement metrics (Cq, RF).
• Direct comparison of Cq values between different assays can be misleading.
• This evaluation offers crucial insights for selecting MPXV diagnostic assays in standard laboratory settings.