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

22The COVID-19 pandemic has severely disrupted worldwide supplies of viral transport media 23 (VTM) due to widespread demand for SARS-CoV-2 RT-PCR testing. In response to this 24 ongoing shortage, we began production of VTM in-house in support of diagnostic testing in our 25 hospital network. As our diagnostic laboratory was not equipped for reagent production, we took 26 advantage of space and personnel that became available due to closure of the research division of 27 our medical center. We utilized a formulation of VTM described by the CDC that was simple to 28 produce, did not require filtration for sterilization, and used reagents that were available from 29 commercial suppliers. Performance of VTM was evaluated by several quality assurance 30 measures. Based on Ct values of spiking experiments, we found that our VTM supported highly 31 consistent amplification of the SARS-CoV-2 target (coefficient of variation = 2.95%) using the 32 Abbott RealTime SARS-CoV-2 EUA assay on the Abbott m2000 platform. VTM was also found 33 to be compatible with multiple swab types and, based on accelerated stability studies, able to 34 maintain functionality for at least four months at room temperature. We further discuss how we 35 met logistical challenges associated with large-scale VTM production in a crisis setting including 36 use of staged, assembly line for VTM transport tube production. 37 38 on June 9, 2020 by guest http://jcm.asm.org/ Downloaded from 39The COVID-19 pandemic has led to an unprecedented need for diagnostic testing. The ideal specimen type is currently believed to be a nasopharyngeal (NP) swab 41 specimen transported to a molecular microbiology laboratory in viral transport medium (VTM). 42Starting in March 2020, increasing demand for testing led to a national shortage of both NP 43 swabs and VTM that created significant bottlenecks in large-scale testing efforts. 44VTM exists in several formulations, all of which consist of a buffered salt solution, a 45 complex source of protein and/or amino acids, and antimicrobial agents. Its purpose is to 46 preserve virus for later amplification by NAAT technology and/or viral culture. Although 47 simpler formulations, for example, saline, are technically compatible with RT-PCR, most NAAT 48 assays for respiratory pathogens have been developed and FDA-cleared for use with more 49 complex transport media (i.e. VTM and universal transport medium, UTM). Overgrowth of 50 bacteria may also occur in media lacking antimicrobial agents. As such, we chose to reproduce a 51 standard of care transport medium to serve our healthcare network. 52In response to the COVID-19 pandemic, our molecular microbiology laboratory was able 53 to quickly scale up SARS-CoV-2 RT-PCR testing to approximately 1000 tests per day to support 54 the needs of our hospital network. However, national shortages of collection materials including 55 nasopharyngeal swabs and VTM were projected to limit our ability to continue testing at this 56 level. We discuss a nationwide collaborative effort to prod...

SARS-CoV2 Testing: The Limit of Detection Matters

“…Repeat tests were excluded in order to more accurately estimate the range of Ct values of the infected population upon presentation at our medical center. In our internal validation we determined that the LoD with 100% detection for the Abbott m2000 platform was 100 copies/mL (n=80), with Ct mean and standard deviation at this LoD, 26.06±1.03 (4). Note, the Ct determination on Abbott M2000rt platform is alternatively called the fractional cycle number (FCN) and is specifically one way of determining the cycle number at the maximum amplification efficiency inflection point, i.e, the maxRatio, of each amplification curve (6).…”

“…Here we report on the reliability of Cts for the Abbott SARS-CoV-2 EUA (LoD 100 copies viral RNA/mL transport medium, among the best in class) (4) and a conversion from Ct to viral load, which together support the use of reporting viral loads clinically, and also on an observation based on over 4,700 first-time positive results that makes it possible to estimate the clinical sensitivity and false-negative rate of both this assay and other assays that have received EUA for detecting SARS-CoV-2 infection. These findings have clear implications for patient care, epidemiology, and the social and economic management of the ongoing pandemic.…”

High stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA under minimal storage conditions for detection by Real-Time PCR

“…The World Health Organization (WHO) recommends cooled storage (2-8°C) and the transport of respiratory specimens in specific viral transport medium (VTM) up to 5 days [3] . Viral transport medium exists in several formulas, all consisting of a buffered salt solution, a complex source of protein and/or amino acids, and antimicrobial agents [5] . As an alternative to the commercially available products, the CDC provided a standard operating procedure for the production of viral transport medium suitable for viral detection [6] .…”

“…The COVID-19 pandemic and the associated demand of mass testing have severely challenged worldwide supplies of commercial viral transport media as well as commercial swab kits and reagents for SARS-CoV-2 RT-PCR [5,6] . Due to the increased demand and the shortage in supply, the compatibility of alternative minimal transport buffers, such as 0.9% saline solution, with viral detection in diagnostics have to be assessed.…”

Detection of SARS-CoV-2 by Real-Time PCR under challenging pre-analytical conditions reveals independence of swab media and cooling chain

“…The World Health Organization (WHO) recommends cooled storage (2-8 °C) and the transport of respiratory specimens in speci c viral transport medium (VTM) up to 5 days [3] . Viral transport medium exists in several formulas, all consisting of a buffered salt solution, a complex source of protein and/or amino acids, and antimicrobial agents [5] . As an alternative to the commercially available products, the CDC provided a standard operating procedure for the production of viral transport medium suitable for viral detection [6] .…”