Credit: Nikhil S. Sahajpal
Schematic overview of sample processing and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay workflow, depicting main steps. Matched nasopharyngeal swab (NPS) and saliva sample pairs collected in health care and community settings were tested and validated as follows. Top panel: NPS or saliva samples were processed with protocol U for nucleic acid extraction using a semi-automated instrument, followed by RT-PCR for N and ORF1ab gene targets and internal control (IC) used as extraction and RT-PCR IC. Middle panel: Saliva samples processed with SalivaAll protocol that included a saliva homogenization step using a bead mill homogenizer before RNA extraction and downstream processing. Bottom panel: Saliva samples were homogenized using a bead mill homogenizer (SalivaAll protocol) before pooling samples with a five-sample pooling strategy for SARS-CoV-2 testing.