Performance Analysis of Self-Collected Nasal and Oral Swabs for Detection of SARS-CoV-2

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the third highly pathogenic human coronavirus and is rapidly transmitted by infected individuals regardless of their symptoms. During the COVID-19 pandemic, owing to the dearth of skilled healthcare workers (HCWs) to collect samples for early diagnosis, self-collection emerged as a viable alternative. To evaluate the reliability of self-collection, we compared the virus detection rate using 3990 self-collected swabs and HCW-collected swabs, procured from the same individuals and collected immediately after the self-collection. The results of multiplex reverse-transcription quantitative polymerase chain reaction revealed that the viral load in the HCW-collected swabs was marginally (18.4–28.8 times) higher than that in self-collected swabs. Self-collection showed no significant difference in sensitivity and specificity from HCW-collection (κ = 0.87, McNemar’s test; p = 0.19), indicating a comparable performance. These findings suggest that self-collected swabs are acceptable substitutes for HCW-collected swabs, and that their use improved the specimen screening efficiency and reduced the risk of SARS-CoV-2 infection among HCWs during and after the COVID-19 pandemic.

Evaluation of Covid-19 Ag-RDTs self-testing in Lesotho and Zambia

“…Most of the research on self-testing actually assessed self-sampling and not the complete self-testing process. Such studies indicated that high quality samples can be taken by users, with self-taken samples tested against PCR yielding sensitivities and specificities close to, or above the WHO's target product profile recommended sensitivity and specificity thresholds of 80% and 97% (19)(20)(21)(22)(23)(24)(26)(27)(28). Regarding the complete self-testing process (i.e.…”

“…However, when participants were observed in Zambia, a considerable number of participants had difficulties following some of the steps correctly. Some of these difficulties such as removing the swab from the tube and extracting the liquid from the swab were also observed to be difficult for participants in the study in Malawi and Zimbabwe assessing usability of the same tests [23]. The study population in Malawi and Zimbabwe included health workers, who can be expected to be familiar with the testing process and able to understand instruction and to self-test easily compared to other populations.…”

“…sample type, reference standard, population), making it difficult to test for operator effects; if the ability to perform the self-test depends on user characteristics such as literacy, health literacy and previous testing experience. There is evidence from studies in high income settings assessing performance of self-sampling tested against Polymerase Chain Reaction (PCR), with reported yields close to or over the WHO sensitivity and specificity thresholds of 80% and 97% respectively (19)(20)(21)(22)(23)(24). It is necessary to expand on these findings and assess whether both self-collection of samples and self-testing can be accurately performed by the general population in LMICs.…”

Evaluation of Four Rapid Antigen Tests for the Detection of SARS-CoV-2 Infection with Nasopharyngeal Swabs

“…The thermal cycling conditions were as follows: 50 °C for 20 min; 95 °C for 15 min; and 45 cycles at 95 °C for 10 s, 60 °C for 15 s, and 72 °C for 10 s. The data were analyzed using Seegene Viewer (v3.24; Seegene Inc.). The results were interpreted as SARS-CoV-2 positive when the Ct value was ≤40 for all targets, according to the manufacturer’s instructions [ 9 ]. Of these, RdRP and S were represented by a Ct value from rRT-PCR in this study.…”

“…The rRT-PCR assay is the gold-standard test for SARS-CoV-2 detection, especially when using nasopharyngeal swabs (NPSs) obtained from suspected cases by trained healthcare workers [ 9 ]. However, rRT-PCR assays have a turnaround time of approximately 24–48 h, which results in a bottleneck in PCR testing during the peak period of SARS-CoV-2 infections, which adversely affects the management of patients with COVID-19 [ 10 ].…”