Validation of a 3-Dimensionally Printed Nasopharyngeal Swab for SARS-CoV-2 Testing | Medical Devices and Equipment | JN Learning | AMA Ed Hub [Skip to Content]
[Skip to Content Landing]

Design and Multicenter Clinical Validation of a 3-Dimensionally Printed Nasopharyngeal Swab for SARS-CoV-2 Testing

Educational Objective
To identify the key insights or developments described in this article
1 Credit CME
Key Points

Question  Is a novel 3-dimensionally printed nasopharyngeal swab (3DP swab) accurate in detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)?

Findings  In this diagnostic study for coronavirus disease 2019 (COVID-19) across 2 institutions of 79 patients with COVID-19 and 10 controls, the overall agreement and positive percentage agreement of the 3DP swab was 91.1% and 93.5%, respectively, compared with the traditional FLOQSwab (COPAN Diagnostics) and Dacron swab (Deltalab). The positive percentage agreement was 100% for COVID-19 cases tested within the first week of illness, and reverse-transcriptase polymerase chain reaction cycle threshold values for the ORF1ab and E-gene targets showed a strong correlation between the 3DP and traditional swab on independent testing at each institution despite differences in sample processing.

Meaning  The 3DP swab performed accurately and consistently across health care institutions and may help mitigate strained resources in the escalating COVID-19 pandemic.

Abstract

Importance  Three-dimensionally printed nasopharyngeal swabs (3DP swabs) have been used to mitigate swab shortages during the coronavirus disease 2019 (COVID-19) pandemic. Clinical validation for diagnostic accuracy and consistency, as well as patient acceptability, is crucial to evaluate the swab’s performance.

Objective  To determine the accuracy and acceptability of the 3DP swab for identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Design, Setting, and Participants  A diagnostic study was conducted from May to July 2020 at 2 tertiary care centers in Singapore with different reference swabs (FLOQSwab [COPAN Diagnostics] or Dacron swab [Deltalab]) and swab processing techniques (wet or dry) to evaluate the performance of the 3DP swab compared with traditional, standard-of-care nasopharyngeal swabs used in health care institutions. The participants were patients with COVID-19 in the first 2 weeks of illness and controls with acute respiratory illness with negative test results for SARS-CoV-2. Paired nasopharyngeal swabs were obtained from the same nostril and tested for SARS-CoV-2 by reverse-transcriptase polymerase chain reaction. The sequence of swabs was randomized based on odd and even participant numbers.

Main Outcomes and Measures  Primary outcome measures were overall agreement (OA), positive percentage agreement (PPA), and negative percentage agreement of the 3DP swab compared with reference swabs. Secondary outcome measures were the correlation of cycle threshold (Ct) values of both swabs.

Results  The mean (SD) age of participants was 45.4 (13.1) years, and most participants were men (87 of 89 [97.8%]), in keeping with the epidemiology of the COVID-19 pandemic in Singapore. A total of 79 patients with COVID-19 and 10 controls were recruited. Among the patients with COVID-19, the overall agreement and PPA of the 3DP swab was 91.1% and 93.5%, respectively, compared with reference swabs. The PPA was 100% for patients with COVID-19 who were tested within the first week of illness. All controls tested negative. The reverse-transcriptase polymerase chain reaction Ct values for the ORF1ab and E-gene targets showed a strong correlation (intraclass correlations coefficient, 0.869-0.920) between the 3DP and reference swab on independent testing at each institution despite differences in sample processing. Discordant results for both gene targets were observed only at high Ct values.

Conclusions and Relevance  In this diagnostic study of 79 patients with COVID-19 and 10 controls, the 3DP swab performed accurately and consistently across health care institutions and could help mitigate strained resources in the escalating COVID-19 pandemic.

Sign in to take quiz and track your certificates

Buy This Activity

JN Learning™ is the home for CME and MOC from the JAMA Network. Search by specialty or US state and earn AMA PRA Category 1 CME Credit™ from articles, audio, Clinical Challenges and more. Learn more about CME/MOC

Article Information

Accepted for Publication: December 22, 2020.

Published Online: February 18, 2021. doi:10.1001/jamaoto.2020.5680

Corresponding Author: David M. Allen, MD, Division of Infectious Diseases, Department of Medicine, National University of Singapore, 1E Kent Ridge Rd, Singapore 119228 (mdcdma@nus.edu.sg).

Author Contributions: Drs Tay and Allen had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Drs Tay and Dr Cross are equal contributors.

Concept and design: Tay, Cross, Toh, J. Loh, Z. Lim, W. Chow, Goh, Siow, K. Loh, Chua, H. Tan, Chan, Wang, Fuh, Yen, Wong, Allen.

Acquisition, analysis, or interpretation of data: Tay, Cross, Toh, Lee, J. Loh, Z. Lim, Ngiam, Chee, Gan, Saraf, Lian, W. Loh, C. Lim, T. Tan, Yan, Ko, Oon, V. Chow, Wang, Allen.

Drafting of the manuscript: Tay, Cross, Toh, Z. Lim, Chee, Gan, Saraf, Yan, Chan, Yen, Allen.

Critical revision of the manuscript for important intellectual content: Tay, Cross, Toh, Lee, J. Loh, Ngiam, Chee, W. Chow, Goh, Siow, Lian, W. Loh, K. Loh, C. Lim, Chua, T. Tan, H. Tan, Ko, Oon, V. Chow, Wang, Fuh, Yen, Wong, Allen.

Statistical analysis: Tay, Z. Lim, Ko, V. Chow.

Obtained funding: K. Loh, Wong.

Administrative, technical, or material support: Cross, Toh, Lee, J. Loh, Z. Lim, Ngiam, Chee, W. Chow, Goh, Siow, Lian, K. Loh, Chua, H. Tan, Chan, V. Chow, Wang, Fuh, Yen, Wong.

Supervision: Cross, K. Loh, Yan, Chan, V. Chow, Wang, Yen, Wong, Allen.

Other - Conduct of the trial: Cross.

Other - conduct experiment: Gan.

Other - mechanical testing: Saraf.

Other - SGH data: Ko.

Conflict of Interest Disclosures: Dr Yen and Mr Chow reported a patent filed by the National University of Singapore describing the design of the 3-dimensionally printed nasopharyngeal swab reported in this article. All clinical aspects of the study (clinical testing, analysis and interpretation) were performed independently from the swab design team, including Dr Yen and Mr Chow. No other disclosures were reported.

Funding/Support: This study was supported in part by the National Medical Research Council, Singapore (grant NMRC/CIRG18nov-0045) and the National Research Foundation, Singapore under its International Research Centres in Singapore Funding Initiative.

Role of the Funder/Sponsor: The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not reflect the views of National Medical Research Council or the National Research Foundation, Singapore.

Additional Contributions: We acknowledge the support of our medical colleagues and patient participants during the clinical study, as well as the National University Hospital Operating Theatre for their support in sterilizing the 3DP swabs. We thank Paul A. Tambyah, MD, for advice on the study design. We thank Chaw Sing Ho, PhD, and the National Additive Manufacturing Innovation Cluster Singapore for their coordinating efforts between stakeholders and regulatory agencies. Images of the final swab were also contributed by Eye-2-Eye Communications and Structo. Data from the mechanical testing was kindly provided by TÜV SÜD PSB Singapore.

Additional Information: The data shown in this article are available on request from the corresponding author. Anonymized cycle threshold values and day of illness for the clinical validation study are included in eMethods in the Supplement.

References
1.
Dong  E , Du  H , Gardner  L .  An interactive web-based dashboard to track COVID-19 in real time.   Lancet Infect Dis. 2020;20(5):533-534. doi:10.1016/S1473-3099(20)30120-1 PubMedGoogle ScholarCrossref
2.
World Health Organization. 2019 Novel coronavirus: strategic preparedness and response plan. Accessed November 26, 2020. https://www.who.int/publications/i/item/strategic-preparedness-and-response-plan-for-the-new-coronavirus
3.
Bagdasarian  N , Fisher  D .  Heterogenous COVID-19 transmission dynamics within Singapore: a clearer picture of future national responses.   BMC Med. 2020;18(1):164. doi:10.1186/s12916-020-01625-7 PubMedGoogle ScholarCrossref
4.
Team C-NIRS.  COVID-19, Australia: epidemiology report 20 (fortnightly reporting period ending 5 July 2020).   Commun Dis Intell. 2020;44. doi:10.33321/cdi.2020.44.75Google Scholar
5.
Devi  S .  COVID-19 resurgence in Iran.   Lancet. 2020;395(10241):1896. doi:10.1016/S0140-6736(20)31407-0 PubMedGoogle ScholarCrossref
6.
Yelin  I , Aharony  N , Tamar  ES ,  et al.  Evaluation of COVID-19 RT-qPCR test in multi-sample pools.   Clin Infect Dis. 2020;71(16):2073-2078. doi:10.1093/cid/ciaa531 PubMedGoogle ScholarCrossref
7.
Smith  KP , Cheng  A , Chopelas  A ,  et al.  Large-scale, in-house production of viral transport media to support SARS-CoV-2 PCR testing in a multihospital healthcare network during the COVID-19 pandemic.   J Clin Microbiol. 2020;58(8):e00913-e00920. doi:10.1128/JCM.00913-20 PubMedGoogle ScholarCrossref
8.
Vermeiren  C , Marchand-Senécal  X , Sheldrake  E ,  et al.  Comparison of Copan Eswab and FLOQswab for COVID-19 PCR diagnosis: working around a supply shortage.   J Clin Microbiol. 2020;58(6):e00669-e20. doi:10.1128/JCM.00669-20 PubMedGoogle ScholarCrossref
9.
Callahan  CJ , Lee  R , Zulauf  KE ,  et al.  Open development and clinical validation of multiple 3D-printed nasopharyngeal collection swabs: rapid resolution of a critical COVID-19 testing bottleneck.   J Clin Microbiol. 2020;58(8):e00876-e20. doi:10.1128/JCM.00876-20 PubMedGoogle ScholarCrossref
10.
Cox  JL , Koepsell  SA .  3D-printing to address COVID-19 testing supply shortages.   Lab Med. 2020;51(4):e45-e46. doi:10.1093/labmed/lmaa031 PubMedGoogle ScholarCrossref
11.
Donner  A , Rotondi  MA .  Sample size requirements for interval estimation of the kappa statistic for interobserver agreement studies with a binary outcome and multiple raters.   Int J Biostat. 2010;6(1):31. doi:10.2202/1557-4679.1275 PubMedGoogle ScholarCrossref
12.
Koo  TK , Li  MY .  A guideline of selecting and reporting intraclass Correlation Coefficients for Reliability Research.   J Chiropr Med. 2016;15(2):155-163. doi:10.1016/j.jcm.2016.02.012 PubMedGoogle ScholarCrossref
13.
Osterblad  M , Järvinen  H , Lönnqvist  K ,  et al.  Evaluation of a new cellulose sponge-tipped swab for microbiological sampling: a laboratory and clinical investigation.   J Clin Microbiol. 2003;41(5):1894-1900. doi:10.1128/JCM.41.5.1894-1900.2003 PubMedGoogle ScholarCrossref
14.
Kim  H , Hong  H , Yoon  SH .  Diagnostic performance of CT and reverse transcriptase polymerase chain reaction for coronavirus disease 2019: a meta-analysis.   Radiology. 2020;296(3):E145-E155. doi:10.1148/radiol.2020201343 PubMedGoogle ScholarCrossref
15.
World Health Organization. Molecular assays to diagnose COVID-19: Summary table of available protocols. Accessed August 14, 2020. https://www.who.int/publications/m/item/molecular-assays-to-diagnose-covid-19-summary-table-of-available-protocols
16.
Chang  MC , Hur  J , Park  D .  Interpreting the COVID-19 test results: a guide for physiatrists.   Am J Phys Med Rehabil. 2020;99(7):583-585. doi:10.1097/PHM.0000000000001471 PubMedGoogle ScholarCrossref
17.
Decker  SJ , Goldstein  TA , Ford  JM ,  et al.  3D printed alternative to the standard synthetic flocked nasopharyngeal swabs used for COVID-19 testing.   Clin Infect Dis. 2020;ciaa1366. doi:10.1093/cid/ciaa1366 PubMedGoogle Scholar
18.
La Scola  B , Le Bideau  M , Andreani  J ,  et al.  Viral RNA load as determined by cell culture as a management tool for discharge of SARS-CoV-2 patients from infectious disease wards.   Eur J Clin Microbiol Infect Dis. 2020;39(6):1059-1061. doi:10.1007/s10096-020-03913-9 PubMedGoogle ScholarCrossref
19.
Bullard  J , Dust  K , Funk  D ,  et al.  Predicting infectious SARS-CoV-2 from diagnostic samples.   Clin Infect Dis. 2020;ciaa638.PubMedGoogle Scholar
20.
National Centre for Infectious Diseases SaCoIDP, Academy of Medicine, Singapore. Period of infectivity to inform strategies for de-isolation for COVID-19 patients. Accessed May 24, 2020. https://www.ams.edu.sg/policy-advocacy/covid-19-resource-page
21.
Rybicki  FJ .  3D printing in medicine: COVID-19 testing with 3D printed nasopharyngeal swabs.   Clin Infect Dis. 2020;ciaa1437. doi:10.1093/cid/ciaa1437 PubMedGoogle Scholar
If you are not a JN Learning subscriber, you can either:
Subscribe to JN Learning for one year
Buy this activity
jn-learning_Modal_Multimedia_LoginSubscribe_Purchase
Close
If you are not a JN Learning subscriber, you can either:
Subscribe to JN Learning for one year
Buy this activity
jn-learning_Modal_Multimedia_LoginSubscribe_Purchase
Close
With a personal account, you can:
  • Access free activities and track your credits
  • Personalize content alerts
  • Customize your interests
  • Fully personalize your learning experience
Education Center Collection Sign In Modal Right
Close

Name Your Search

Save Search
Close
With a personal account, you can:
  • Track your credits
  • Personalize content alerts
  • Customize your interests
  • Fully personalize your learning experience
jn-learning_Modal_SaveSearch_NoAccess_Purchase
Close

Lookup An Activity

or

Close

My Saved Searches

You currently have no searches saved.

Close
With a personal account, you can:
  • Access free activities and track your credits
  • Personalize content alerts
  • Customize your interests
  • Fully personalize your learning experience
Education Center Collection Sign In Modal Right
Close