Comparison of Self-Collected Oral-Nasal and Mid-turbinate Swabs to Healthcare Worker-Collected Nasopharyngeal Swabs for the Detection of SARS-CoV-2

Accurate detection of respiratory viruses is essential for infection control, patient management, and public health response. Nasopharyngeal swabs (NPS), collected by healthcare workers (HWC-NPS), remain the gold standard for SARS-CoV-2 detection but require trained personnel and can be uncomfortable for patients. Self-collected swabs, such as oral–nasal swabs (SC-ONS) and mid-turbinate swabs, offer scalable alternatives suitable for mass testing. This study compared the performance of i) SC-ONS, ii) an automation-friendly, redesigned version of mid-turbinate swab (SC-MTS), and ii) HWC-NPS in detecting SARS-CoV-2. Between April and June 2022, paired NPS, ONS, and MTS samples were collected from 100 participants at a COVID-19 assessment centre in Hamilton, ON. Samples were tested for SARS-CoV-2 by RT-PCR. Compared to HWC-NPS, SC-ONS demonstrated 82.1% sensitivity and 100% specificity, while SC-MTS showed 75.0% sensitivity and 100% specificity. Agreement with HWC-NPS was strong for both SC-ONS (κ=0.863) and SC-MTS (κ=0.804). Agreement between SC-ONS and SC-MTS was nearly perfect (κ=0.944). Cellular material yields as well as SARS-CoV-2 viral loads were lower for self-collected swabs than HWC-NPS, while viral load comparisons revealed no significant difference between SC-ONS and SC-MTS. Our results suggest that self-collected ONS and MTS are reliable alternatives to HWC-NPS, offering practical, less invasive, and automation-compatible options for large-scale respiratory virus surveillance and pandemic preparedness.