Performance of Unobserved Self-Collected Nasal Swabs for Detection of SARS-CoV-2 by RT-PCR Utilizing a Remote...

Area of Science:

• Infectious Diseases
• Molecular Diagnostics
• Public Health

Background:

• Remote specimen collection for SARS-CoV-2 (COVID-19) RT-PCR reduces personal protective equipment (PPE) use and exposure risk.
• Unobserved self-collection kits enable remote testing strategies.
• Assessing self-collection's impact on test performance is crucial for widespread screening programs.

Purpose of the Study:

• To evaluate the performance of SARS-CoV-2 RT-PCR testing using self-collected anterior nasal swabs.
• To determine the impact of unobserved specimen self-collection on test accuracy.
• To assess the feasibility and effectiveness of pooled testing strategies in a self-collection cohort.

Main Methods:

• Utilized Quest Diagnostics SARS-CoV-2 RT-PCR for self-collected anterior nasal swabs from an employee return-to-work program.
• Tabulated cycle threshold (Ct) values for N-gene targets (N1, N3) and human RNase P (RP) control.
• Compared Ct values with a cohort of health care provider-collected specimens.

Main Results:

• 1.8% positivity rate among 47,923 participants.
• Minimal failure rate (0.011%) for the RP control gene.
• Median Ct values for self-collected specimens were higher than for symptomatic patients, but comparable to asymptomatic patients.
• Pooled testing (4 specimens) showed a 5.2% inconclusive rate but only one false-negative result.

Conclusions:

• Unobserved self-collection of nasal swabs provides adequate sampling for SARS-CoV-2 RT-PCR.
• Concerns regarding increased false negatives with self-collection are alleviated.
• Specimen pooling is a viable strategy for self-collected samples, with a low false-negative risk using sensitive, dual-target assays.