Nasal Swab Sampling for SARS-CoV-2: a Convenient Alternative in Times of Nasopharyngeal Swab Shortage

AbstractThe advent of the COVID-19 pandemic in the United States created a unique situation where multiple molecular diagnostic assays with various indications for use in the detection of SARS-CoV-2 rapidly received Emergency Use Authorization by the FDA, were validated by laboratories and utilized clinically, all within a period of a few weeks. We compared the performance of four of these assays that were being evaluated for use at our institution: Abbott RealTime m2000 SARS-CoV-2 Assay, DiaSorin Simplexa COVID-19 Direct, Cepheid Xpert Xpress SARS-CoV-2 and Abbott ID NOW COVID-19. Nasopharyngeal and nasal specimens were collected from 88 ED and hospital-admitted patients and tested by the four methods in parallel to compare performance. ID NOW performance stood out as significantly worse than the other three assays despite demonstrating comparable analytic sensitivity. Further study determined that the use of a foam nasal swab compared to a nylon flocked nasopharyngeal swab, as well as use in a population chronically vs. acutely positive for SARS-CoV-2, were significant factors in the poor comparable performance.

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Detection of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in outpatients: A multicenter comparison of self-collected saline gargle, oral swab, and combined oral–anterior nasal swab to a provider collected nasopharyngeal swab

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2021.2 ◽

2021 ◽

pp. 1-5

Author(s):

Christopher E. Kandel ◽

Matthew Young ◽

Mihaela Anca Serbanescu ◽

Jeff E. Powis ◽

David Bulir ◽

...

Keyword(s):

Nasal Swab ◽

Underserved Populations ◽

Nasopharyngeal Swab ◽

Assessment Centers ◽

Reference Standard ◽

Threshold Values ◽

Oral Swab ◽

Nasal Swabs ◽

Respiratory Coronavirus ◽

Adjusted Sensitivity

Abstract Background: Widespread testing for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) is necessary to curb the spread of coronavirus disease 2019 (COVID-19), but testing is undermined when the only option is a nasopharyngeal swab. Self-collected swab techniques can overcome many of the disadvantages of a nasopharyngeal swab, but they require evaluation. Methods: Three self-collected non-nasopharyngeal swab techniques (saline gargle, oral swab and combined oral-anterior nasal swab) were compared to a nasopharyngeal swab for SARS-CoV-2 detection at multiple COVID-19 assessment centers in Toronto, Canada. The performance characteristics of each test were assessed. Results: The adjusted sensitivity of the saline gargle was 0.90 (95% CI 0.86-0.94), the oral swab was 0.82 (95% CI, 0.72–0.89) and the combined oral–anterior nasal swab was 0.87 (95% CI, 0.77–0.93) compared to a nasopharyngeal swab, which demonstrated a sensitivity of ˜90% when all positive tests were the reference standard. The median cycle threshold values for the SARS-CoV-2 E-gene for concordant and discordant saline gargle specimens were 17 and 31 (P < .001), for the oral swabs these values were 17 and 28 (P < .001), and for oral–anterior nasal swabs these values were 18 and 31 (P = .007). Conclusions: Self-collected saline gargle and an oral–anterior nasal swab have a similar sensitivity to a nasopharyngeal swab for the detection of SARS-CoV-2. These alternative collection techniques are cheap and can eliminate barriers to testing, particularly in underserved populations.

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Evaluation of Rapid Antigen Tests Using Nasal Samples to Diagnose SARS-CoV-2 in Symptomatic Patients

Frontiers in Public Health ◽

10.3389/fpubh.2021.728969 ◽

2022 ◽

Vol 9 ◽

Author(s):

Manaf Alqahtani ◽

Abdulkarim Abdulrahman ◽

Fathi Mustafa ◽

Abdulla I. Alawadhi ◽

Batool Alalawi ◽

...

Keyword(s):

Early Detection ◽

Nasal Swab ◽

Cost Effective ◽

Nasopharyngeal Swab ◽

Rt Pcr ◽

Rapid Antigen Detection Test ◽

Viral Loads ◽

Antigen Tests ◽

Stratified Analysis ◽

Potential Use

IntroductionThe best way to mitigate an outbreak besides mass vaccination is via early detection and isolation of infected cases. As such, a rapid, cost-effective test for the early detection of COVID-19 is required.MethodsThe study included 4,183 mildly symptomatic patients. A nasal and nasopharyngeal sample obtained from each patient was analyzed to determine the diagnostic ability of the rapid antigen detection test (RADT, nasal swab) in comparison with the current gold-standard (RT-PCR, nasopharyngeal swab).ResultsThe calculated sensitivity and specificity of the RADT was 82.1 and 99.1%, respectively. Kappa's coefficient of agreement between the RADT and RT-PCR was 0.859 (p < 0.001). Stratified analysis showed that the sensitivity of the RADT improved significantly when lowering the cut-off RT-PCR Ct value to 24.ConclusionOur study's results support the potential use of nasal swab RADT as a screening tool in mildly symptomatic patients, especially in patients with higher viral loads.

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Excellent option for mass testing during the SARS-CoV-2 pandemic: painless self-collection and direct RT-qPCR

Virology Journal ◽

10.1186/s12985-021-01567-3 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Eva Kriegova ◽

Regina Fillerova ◽

Milan Raska ◽

Jirina Manakova ◽

Martin Dihel ◽

...

Keyword(s):

Cohort Study ◽

Early Identification ◽

Nasal Swab ◽

Healthcare Personnel ◽

Nasopharyngeal Swab ◽

Grey Zone ◽

Predictive Values ◽

Nasal Swabs ◽

Large Prospective Cohort Study ◽

Large Prospective Cohort

AbstractThe early identification of asymptomatic yet infectious cases is vital to curb the 2019 coronavirus (COVID-19) pandemic and to control the disease in the post-pandemic era. In this paper, we propose a fast, inexpensive and high-throughput approach using painless nasal-swab self-collection followed by direct RT-qPCR for the sensitive PCR detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This approach was validated in a large prospective cohort study of 1038 subjects, analysed simultaneously using (1) nasopharyngeal swabs obtained with the assistance of healthcare personnel and analysed by classic two-step RT-qPCR on RNA isolates and (2) nasal swabs obtained by self-collection and analysed with direct RT-qPCR. Of these subjects, 28.6% tested positive for SARS-CoV-2 using nasopharyngeal swab sampling. Our direct RT-qPCR approach for self-collected nasal swabs performed well with results similar to those of the two-step RT-qPCR on RNA isolates, achieving 0.99 positive and 0.98 negative predictive values (cycle threshold [Ct] < 37). Our research also reports on grey-zone viraemia, including samples with near-cut-off Ct values (Ct ≥ 37). In all investigated subjects (n = 20) with grey-zone viraemia, the ultra-small viral load disappeared within hours or days with no symptoms. Overall, this study underscores the importance of painless nasal-swab self-collection and direct RT-qPCR for mass testing during the SARS-CoV-2 pandemic and in the post-pandemic era.

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Self-Collected Oral Fluid and Nasal Swabs Demonstrate Comparable Sensitivity to Clinician Collected Nasopharyngeal Swabs for Covid-19 Detection

10.1101/2020.04.11.20062372 ◽

2020 ◽

Cited By ~ 28

Author(s):

N Kojima ◽

F Turner ◽

V Slepnev ◽

A Bacelar ◽

L Deming ◽

...

Keyword(s):

Healthcare Workers ◽

Oral Fluid ◽

Nasal Swab ◽

Quantitative Polymerase Chain Reaction ◽

False Negative ◽

The United States ◽

Rapid Expansion ◽

Nasopharyngeal Swab ◽

Sample Type ◽

Specimen Type

AbstractBackgroundCurrently, there is a pandemic caused by the 2019 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes Covid-19. We wanted to compare specimen types and collection methods to explore if a simpler to collect specimen type could expand access to testing.MethodsWe recruited individuals recently tested for SARS-CoV-2 infection through a “drive-through” testing program. In participants’ homes, we assessed the performance of self-collected oral fluid swab specimens with and without clinician supervision, clinician-supervised self-collected mid-turbinate (nasal) swab specimens, and clinician-collected nasopharyngeal swab specimens. We tested specimens with a validated reverse transcription-quantitative polymerase chain reaction assay for the detection of SARS-CoV-2 and measured cycle threshold values. Symptom status and date of onset of symptoms was also recorded for each participant.ResultsWe recruited 45 participants. The median age of study participant was 42 years old (Interquartile range, 31 to 52 years). Of the participants, 29 had at least one specimen test positive for SARS-CoV-2. Of those, 21 (73%) of 29 reported active symptoms. By specimen type and home-based collection method, clinician-supervised self-collected oral fluid swab specimens detected 26 (90%) of 29 infected individuals, clinician-supervised self-collected nasal swab specimens detected 23 (85%) of 27, clinician-collected posterior nasopharyngeal swab specimens detected 23 (79%) of 29, and unmonitored self-collected oral fluid swab specimens detected 19 (66%) of 29. Despite nasopharyngeal swabs being considered the gold standard, 4 participants tested negative by clinician-collected nasopharyngeal swab and positive by the 3 other specimen types. Additionally, false negative results by each sample type were seen to generally not overlap.ConclusionsSupervised self-collected oral fluid and nasal swab specimens performed similarly to, if not better than clinician-collected nasopharyngeal swab specimens for the detection of SARS-CoV-2 infection. No sample type captured all SARS-CoV-2 infections, suggesting potential heterogeneity in the distribution of viral load in different parts of the respiratory tract between individuals. Supervised self-collection performed comparably to clinician collection and would allow for rapid expansion of testing capacity in the United States by reducing the need for trained healthcare workers, reducing exposure of healthcare workers, and reducing the amount of PPE (personal protective equipment) being used for testing during a critical shortage.

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Self-Collected Oral Fluid and Nasal Swab Specimens Demonstrate Comparable Sensitivity to Clinician-Collected Nasopharyngeal Swab Specimens for the Detection of SARS-CoV-2

Clinical Infectious Diseases ◽

10.1093/cid/ciaa1589 ◽

2020 ◽

Cited By ~ 7

Author(s):

N Kojima ◽

F Turner ◽

V Slepnev ◽

A Bacelar ◽

L Deming ◽

...

Keyword(s):

Oral Fluid ◽

Nasal Swab ◽

Nasopharyngeal Swab ◽

Sample Type

Abstract We compared self-collected oral fluid swab specimens with and without clinician supervision, clinician-supervised self-collected mid-turbinate (nasal) swab specimens, and clinician-collected nasopharyngeal swab specimens for the detection of SARS-CoV-2. Supervised oral fluid and nasal swab specimens performed similarly to clinician-collected nasopharyngeal swab specimens. No sample type could detect SARS-CoV-2 infections amongst all positive participants.

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Optimal Insertion Depth for Nasal Mid-Turbinate and Nasopharyngeal Swabs

Diagnostics ◽

10.3390/diagnostics11071257 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1257

Author(s):

Rasmus Eið Callesen ◽

Cecilie Mullerup Kiel ◽

Lisette Hvid Hovgaard ◽

Kathrine Kronberg Jakobsen ◽

Michael Papesch ◽

...

Keyword(s):

Nasal Swab ◽

False Negative ◽

Inferior Turbinate ◽

Nasopharyngeal Swab ◽

Test Results ◽

Insertion Depth ◽

Specimen Collection ◽

The Mean ◽

Current Guidelines ◽

Virus Testing

Millions of people are tested for COVID-19 daily during the pandemic, and a lack of evidence to guide optimal nasal swab testing can increase the risk of false-negative test results. This study aimed to determine the optimal insertion depth for nasal mid-turbinate and nasopharyngeal swabs. The measurements were made with a flexible endoscope during the collection of clinical specimens with a nasopharyngeal swab at a public COVID-19 test center in Copenhagen, Denmark. Participants were volunteer adults undergoing a nasopharyngeal SARS-CoV-2 rapid antigen test. All 109 participants (100%) completed the endoscopic measurements; 52 (48%) women; 103 (94%) white; mean age 34.39 (SD, 13.2) years; and mean height 176.7 (SD, 9.29) cm. The mean swab length to the posterior nasopharyngeal wall was 9.40 (SD, 0.64) cm. The mean endoscopic distance to the anterior and posterior end of the inferior turbinate was 1.95 (SD, 0.61) cm and 6.39 (SD, 0.62) cm, respectively. The mean depth to nasal mid-turbinate was calculated as 4.17 (SD, 0.48) cm. The optimal depths of insertion for nasal mid-turbinate swabs are underestimated in current guidelines compared with our findings. This study provides clinical evidence to guide the performance of anatomically correct nasal and nasopharyngeal swab specimen collection for virus testing.

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Head-to-head comparison of SARS-CoV-2 antigen-detecting rapid test with self-collected nasal swab versus professional-collected nasopharyngeal swab

European Respiratory Journal ◽

10.1183/13993003.03961-2020 ◽

2020 ◽

pp. 2003961 ◽

Cited By ~ 4

Author(s):

Andreas K. Lindner ◽

Olga Nikolai ◽

Franka Kausch ◽

Mia Wintel ◽

Franziska Hommes ◽

...

Keyword(s):

Nasal Swab ◽

Rapid Test ◽

Nasopharyngeal Swab

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Diagnostic accuracy of nasopharyngeal swab, nasal swab and saliva swab samples for the detection of SARS-CoV-2 using RT-PCR

Infectious Diseases ◽

10.1080/23744235.2021.1903550 ◽

2021 ◽

pp. 1-9

Author(s):

Yoshie Tsujimoto ◽

Junko Terada ◽

Moto Kimura ◽

Ataru Moriya ◽

Ayano Motohashi ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Nasal Swab ◽

Nasopharyngeal Swab ◽

Rt Pcr

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SARS-CoV-2 detection by nasal strips: a superior tool for surveillance of pediatric populations

10.1101/2020.10.28.20220673 ◽

2020 ◽

Author(s):

Renee WY Chan ◽

Kate C Chan ◽

Kathy YY Chan ◽

Grace CY Lui ◽

Joseph GS Tsun ◽

...

Keyword(s):

Sampling Method ◽

Nasal Swab ◽

Diagnostic Yield ◽

False Negative ◽

Viral Rna ◽

Nasopharyngeal Swab ◽

Viral Detection ◽

Community Based ◽

Nucleoprotein Gene ◽

Pcr Targeting

AbstractBackgroundDeep throat saliva (DTS) and pooled nasopharyngeal swab and throat swab (NPSTS) are utilized for viral detection. DTS is challenging for children. Swabbing the respiratory mucosa requires trained personnel and may trigger sneezing and coughing, which generate droplets. A reliable, simple and safe sampling method applicable to a wide age range is required for community-based surveillance.MethodsWe introduced nasal strip as an easy and low-risk collection method. Asymptomatic and symptomatic SARS-CoV-2 infected patients (n = 38) were recruited. Nasal epithelial lining fluid (NELF) (n = 43) strip paired with nasal swab (n = 13) were collected by a healthcare worker to compare with NPSTS (n = 21) or DTS (n =22) collected within 24 hours as reference. All samples were subjected to viral RNA quantitation by real-time PCR targeting the nucleoprotein gene.ResultsComparable Ct values were observed between paired nasal strip and nasal swab samples. The agreement between nasal strip samples and NPSTS was 94.44% and 100% for NPSTS positive and negative samples. Higher viral RNA concentration was detected in nasal strips than DTS samples. False-negative results were recorded in six DTS specimens, of which four were from children. Storage at room temperature up to 72 (n = 3) hours did not affect diagnostic yield of nasal strips.ConclusionsNasal strip is a reliable and non-invasive sampling method for SARS-CoV-2 detection, and viral detection remains stable for at least 72 hours. It can be used as an alternative tool for community-based surveillance.

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