A-377 Lyophilized Respiratory Viruses: A Streamlined Approach to Accessible Precision Quality Control Testing for the Point of Care Environment

Background Quality Control testing is essential to any diagnostics testing platform, but in the point of care (POC) setting, this process can often be cumbersome and frustrating. To minimize barriers to POC molecular quality control testing, an effective quality control system must be room-temperature stable, take up as little shelf space as possible, reliably represent a patient sample, and have a simple, easy-to-follow workflow. Many POC molecular diagnostic systems and their controls satisfy one or two of these requirements, but few (if any) have excelled in all categories. This project aimed to create a lyophilized bead control to meet the complex needs of the point of care environment. Methods Inactivated respiratory viruses (Human Rhinovirus, Respiratory Syncytial Virus, Influenza A and B, and SARS-CoV-2), were contrived into an excipient buffer at concentrations ranging from 32 to 125,000 copies/bead, dispensed into 100 µL pellets, then lyophilized into beads that are rehydrated with a sample collection buffer compatible with the test. The Autonomous Medical Devices Incorporated (AMDI™) Fast PCR System was used as a POC device, but testing was also conducted on traditional extraction platforms and thermocyclers (QiaCube, QuantStudio 5). Bead concentrations were designed to be compatible with specific rehydration volumes to achieve a desired cp/mL concentration. This allowed flexibility to reflect specified multiples of a test’s limit of detection. To ensure precise buffer delivery and therefore rehydration concentration, a volume-definition transfer pipet was used to be compatible with a CLIA-waived environment. Results Early testing for lyophilized beads shows great promise. The physical qualities of the beads are concordant with standard lyophilized reagent usability features: they are resistant to humidity, retain integrity that allows for handling in manufacturing and shipping, and dissolve instantaneously with only a flick. Beads that contain inactivated viral targets at 3.75-7.5X LOD have been run 45 times and returned standard deviations less than 1.5 Cts, even while being run across six AMDI Fast PCR instruments. Results on traditional thermocyclers have also been encouraging, showing CV’s across beads at less than 1%. Little lot-to-lot variability has been observed, with multiple lots at the same concentrations returning Cts within one cycle of each other on a traditional thermocycler. While recently-initiated stability studies for these beads are ongoing, current data shows stability through an accelerated equivalent of 39 days and is planned to continue through one year real-time. Conclusion These lyophilized beads demonstrate potential for a streamlined approach to quality control in the point of care space. The simple workflow of rehydrating a bead, flicking once to mix, then immediately loading into a test cartridge ensures minimal errors, resulting in fewer time spent on quality controls while still giving confidence in test validation. The versatility and highly adaptable nature of these lends utilization to platforms beyond the AMDI Fast PCR system and organisms other than respiratory viruses, making quality control testing more accessible in the POC environment.