In-House Production of Viral Transport Media

In-House Production of Viral Transport Media

The COVID-19 pandemic has led to an unprecedented need for diagnostic reverse transcription-PCR (RT-PCR) testing. The ideal specimen type is currently believed to be a nasopharyngeal (NP) swab specimen transported to a molecular microbiology laboratory in viral transport medium (VTM). Starting in March 2020, increasing demand for testing led to a national shortage of both NP swabs and VTM that created significant bottlenecks in large-scale testing efforts.

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 (CT) 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.

The 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. Furthermore, 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.