We have developed a new Reference Reagent to support the comparison of nucleic acid amplification techniques (NAT) for detection of Monkeypox (Mpox).
This reagent is available now and can be ordered from our NIBSC catalogue.
The reagent contains whole inactivated Clade IIb Mpox virus isolated from a UK patient during the 2022 outbreak. It has been formulated with excipients and lyophilised to maximise long-term stability.
The reagent is intended to compare the performance of Mpox NAT assays across laboratories. Using our in-house NAT assay, analysis of the reconstituted reagent without further dilution yielded a Ct value of 20. However, it is anticipated that different extraction and amplification platforms will yield different results. Users are encouraged to analyse serial dilutions of the reagent, beyond the limit of detection of their chosen assay, and return data to MHRA (at diagidm@mhra.gov.uk) for central analysis. It is hoped that we can collate data from multiple Mpox NAT assays, and thus compare their respective sensitivities.
Our longer-term goal is intended to produce a WHO International Standard for Mpox DNA, value-assigned in International Units (IU), for calibration of NAT assays thus ensuring greater harmonisation between assays. This will also further aid sensitivity assessment of assays by defining limits of detection in a common unit (IU/mL). This reagent will eventually be entered into a multi-laboratory study, along with other candidate materials comprised of other Mpox clades, one of which will ultimately be established as the WHO IS.
This product complements our existing Working Reagent for anti-Mpox antibodies (coded 22/218), intended to aid the development and evaluation of serological assays for Monkeypox antibodies.