Large-Scale, In-House Production of Viral Transport Media To Support SARS-CoV-2 PCR Testing in a Multihospital Health Care Network during the COVID-19 Pandemic

Abstract

The COVID-19 pandemic has severely disrupted worldwide supplies of viral transport media (VTM) due to widespread demand for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcription-PCR (RT-PCR) testing. In response to this ongoing shortage, we began production of VTM in-house in support of diagnostic testing in our hospital network. As our diagnostic laboratory was not equipped for reagent production, we took advantage of space and personnel that became available due to closure of the research division of our medical center. We utilized a formulation of VTM described by the CDC that was simple to produce, did not require filtration for sterilization, and used reagents that were available from commercial suppliers. Performance of VTM was evaluated by several quality assurance measures. Based on cycle threshold (C_T ) values of spiking experiments, we found that our VTM supported highly consistent amplification of the SARS-CoV-2 target (coefficient of variation = 2.95%) using the Abbott RealTime SARS-CoV-2 Emergency Use Authorization (EUA) assay on the Abbott m2000 platform. VTM was also found to be compatible with multiple swab types and, based on accelerated stability studies, able to maintain functionality for at least 4 months at room temperature. We further discuss how we met logistical challenges associated with large-scale VTM production in a crisis setting, including use of a staged assembly line for VTM transport tube production.

Keywords: COVID-19; PCR; SARS-CoV-2; bottleneck; logistics; quality assurance; quality control; supply chain; universal tranport medium; viral transport medium.

FIG 1

Workflow diagram. Each biosafety cabinet was used for all steps in the VTM production workflow. Personnel and the peristaltic pump rotated between cabinets, but tubes remained in place until packaging. (A) First, tubes were loaded and uncapped. (B) Medium filling was then accomplished through use of a peristaltic pump system moved to each biosafety cabinet in turn on a mobile cart. (C) Filled tubes were capped and random samples were subject to QC. (D) Tubes were then removed from the hood, bagged, and sent for distribution. (E) The now-empty hood was then used to start the next production cycle.

FIG 2

Levey-Jennings plot of VTM quality control data. C_T values for VTM lots spiked at 2× the LoD with the SARS-CoV-2 target were plotted each day of testing. Test dates with more than one data point represent the same batch of VTM evaluated for compatibility with multiple swab types (see Table 1).