![]() ![]() This makes it difficult to pipette manually or on an automated liquid handler. Crude saliva is viscous and can congeal shortly after collection 6. ![]() Notwithstanding the benefits of saliva as a simplified alternative to NPS sampling, its practical implementation for high-throughput SARS-CoV-2 detection has proven challenging for diagnostic laboratories 11. This led to Federal Drug Administration (FDA) approving saliva samples and a direct-PCR protocol for saliva testing, called the Saliva Direct 10, for SARS-CoV-2 detection under emergency use authorization (EUA) regulations. The development of “extraction-free” PCR protocols 8, 9 whereby the saliva is directly added to the RT-qPCR assay reaction mixture without extensive RNA purification processing, further enhanced the clinical acceptability of this sample type 5. The empirical observation that the SARS-CoV-2 virus is stable for > 72 h in this matrix 7, and therefore does not require specialized collection devices or preservatives, opened up possibilities of performing at-home, self-administered sample collection. Saliva was the first non-invasive, non-NPS sample type validated and found to have performance similar to the gold standard NPS specimen type 3, 4, 5, 6. To address this, alternative sample types that are easy to administer, preferably by self-collection, were actively sought during the COVID-19 pandemic. Poor performance of NPS sampling can result in false-negative results due to inadequate/improper sample collection. This mode of sample collection has drawbacks, such as discomfort to the patient, and being resource intensive, as it requires a dedicated health care worker (HCW) to accurately collect or oversee the sample collection process. ![]() This described process from sample self-collection to automated direct PCR testing significantly reduces the total burden on healthcare systems in terms of human resources and reagent requirements.Ĭollection of nasopharyngeal swab specimen (NPS) is still considered the gold standard for diagnostic detection of SARS-CoV-2 1, 2. Although the overall turnaround time was only slightly faster in the automated workflow (185 min vs 200 min), there was a 76% reduction in hands-on time, potentially reducing staff fatigue and burnout. Of the 1060 samples tested during validation, 3.6% (39/1060) of samples required retesting as they were either single gene positive, had internal control failure or liquid aspiration error. In both validation and live testing, the assay produced no false positive or false negative results. Use of pre-frozen SARS-CoV-2 assay reaction mixtures reduced assay setup time. ![]() A customized barcode scanning script for reading the sample ID by the Hamilton STARlet’s software system was developed to allow primary tube sampling. This was achieved through elimination of nucleic acid extraction and automation of sample handling on a widely available robotic liquid handler, Hamilton STARlet. We utilized self-collected saline gargle samples to optimize high throughput SARS-CoV-2 multiplex polymerase chain reaction (PCR) testing in order to minimize cost and technologist time. As part of the COVID-19 pandemic, clinical laboratories have been faced with massive increases in testing, resulting in sample collection systems, reagent, and staff shortages. ![]()
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