24Nasopharygneal swabs (NPS) are the collection modality recommended by the Centers for 25 Disease Control and Prevention (CDC) for reverse-transcription polymerase chain reaction (RT-PCR) 26 testing for SARS-CoV2. NPS gather both extracellular material and human respiratory epithelial cells and, 27 when used with RT-PCR, have reliable sensitivity for detection of viral infection. However, at our 28 institution, we identified a 1.7% re-order rate within 7-days for NPS for respiratory pathogen 29 which we hypothesize may be due to low confidence in adequate sample collection. We sought to 30 identify an inexpensive and accessible strategy for benchside quality assurance of NPS adequacy by 31 observing microscopic content of viral transport media. For 801 NPS samples collected in November 32 2019, we air-dried and safranin-stained aliquots of viral transport media on glass slides. We then 33 counted morphologically distinct ciliated columnar epithelial cells (CCEs). 19% of samples negative by 34 RT-PCR for respiratory pathogens had no CCEs, while just 6% of positive samples exhibited the same. 35