• Joshua K Tay, Gail B Cross, Song Tar Toh, Chun Kiat Lee, Jerold Loh, Zhen Yu Lim, Nicholas Ngiam, Jeremy Chee, Soo Wah Gan, Anmol Saraf, Wai Tung Eason Chow, Han Lee Goh, Chor Hiang Siow, Derrick W Q Lian, Woei Shyang Loh, Kwok Seng Loh, Chwee Ming Lim, Ying Ying Chua, Thuan Tong Tan, Hiang Khoon Tan, Benedict Yan, Karrie Ko, Kian Sing Chan, Lynette Oon, ChowVincent T KVTKDepartment of Microbiology and Immunology, National University of Singapore, Singapore., WangDe YunYDepartment of Otolaryngology-Head and Neck Surgery, National University of Singapore, Singapore., Jerry Y H Fuh, Ching-Chiuan Yen, WongJohn E LJELDepartment of Medicine, National University of Singapore, Singapore.Department of Hematology-Oncology, National University Cancer Institute, Singapore., and David M Allen.
• Department of Otolaryngology-Head and Neck Surgery, National University of Singapore, Singapore.
• JAMA Otolaryngol Head Neck Surg. 2021 May 1; 147 (5): 418-425.

ImportanceThree-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.ObjectiveTo determine the accuracy and acceptability of the 3DP swab for identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).Design, Setting, And ParticipantsA 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 MeasuresPrimary 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.ResultsThe 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 RelevanceIn 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.

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