Assessment of SARS-CoV-2 Nasopharyngeal Swab Technique Online: Blinded Expert Content Analysis of YouTube Videos (Preprint)
BACKGROUND Real-time polymerase chain reaction (RT-PCR) of nasopharyngeal swabs (NPS) is currently the most widely used method for testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, false negatives and the sensitivity of this mode of testing have been problematic for accurately estimating the prevalence of SARS-CoV-2 infection rates. OBJECTIVE The purpose of this study was to evaluate whether technical and, therefore, correctable errors were being made with regards to nasopharyngeal swab procedure. METHODS Online video database (Youtube) was queried for SARS-CoV-2 nasopharyngeal swab tests from January 1 to May 15, 2020. Videos were rated by three blinded rhinologists for accuracy of swab angle and depth. The overall score respectively for swab angle and swab depth for each NPS video was determined by the majority score with agreement among at least two out of three reviewers. Video data between YouTube videos with correct NPS technique and videos with incorrect NPS technique were compared. Categorical data were compared using chi-square test for independence and nominal or continuous data were compared using Mann-Whitney U test with statistical significance set at P=0.05. RESULTS 126 videos met inclusion and exclusion criteria. 52% (N=66) of total NPS videos were determined to have correct angle while 46% (N=58) showed appropriate depth. 44% (N=57) of videos had both correct NPS angle and appropriate depth while 48% (N=60) of videos had both incorrect NPS angle and inappropriate depth. Videos with correct NPS technique were associated with the swab operator identifying as a medical professional (96% vs 86%, 2 =4.4, P=0.04) and as an ENT-related medical professional (16% vs 0%, 2 =11.7, P<0.001 ). CONCLUSIONS Greater attention needs to be given towards educating frontline healthcare workers performing NPS, as this study shows that over half of videos documenting NPS show incorrect technique, which could elevate false negative rates.