London Biofoundry testing and pooling projects

In early 2020, due to reagent and labware shortages, there were significant limitations on SARS-CoV-2 testing capacity worldwide, with the UK’s diagnostic capacity at only 10 000 tests per day at the beginning of April. The London Biofoundry worked together with NHS colleagues to successfully increase testing capacity in accredited NHS laboratories at the St Mary’s (Imperial Molecular Diagnostics Unit) and Charing Cross Hospitals in support of patient, hospital staff and Imperial College testing. During Spring 2020 the team prototyped, validated and developed novel robotic platforms that enabled large-scale testing on a reagent kit agnostic platform. These platforms are now central to NHS testing at North West London Pathology (NWLP) and form the basis of the Imperial College Lighthouse Laboratory, together providing capacity for ~7 000 samples per day. Part of the prototyping and validation process involved the production of synthetic virus-like particles which are packaged with SARS-CoV-2 N gene RNA. These virus-like particles can be used as process controls because they are virus mimics designed to closely approximate patient samples without biosafety risks (BSL1). The London Biofoundry are now participating in an international SARS-CoV-2 harmonisation study led by the Coronavirus Standards Working Group (Stanford University) which involves 10 different reference materials including our open source sVLP MS2 particles and several diagnostic testing labs worldwide.

Throughout the year, there has been continued pressure on reagents and consumables and therefore group testing has garnered interest from the NHS for front-line asymptomatic staff testing. In October and November 2020, NWLP and the London Biofoundry conducted an NHS England proof of concept to determine the technical feasibility of adaptive group testing and determined how it could be implemented into the current NHS diagnostic workflow. Intricate mapping of the entire process was used to model bottlenecks of the process. Then, the lower limit of detection of the NWLP diagnostic workflow was determined, which was used together with the prevalence and liquid handling complexity to determine the largest acceptable pool size. Imperial College, Riffyn and NWLP then successfully designed and implemented an adaptive group testing workflow in an NHS diagnostic laboratory, the first implementation of its kind.