Multicentric evaluation of a 3D‐printed simulator for COVID- 19 nasopharyngeal swab collection in testing centers
Authors: Lise Lecointre, Aïna Venkatasamy, Mégane Wehr, Antoine Koch, Axel Sananes, Christian Debry, Massimo Lodi, Nicolas Sananes
Journal: Journal of Infection (2021)

In 2021, reliable knowledge of the COVID status of individuals became a global public health issue, from an epidemiological point of view - to contain the pandemic - but also from an economical one, as repeated testings represent a significant financial burden. COVID-19 diagnosis replies on RT-qPCR from nasopharyngeal swab (NPS) sample, which is considered as the gold standard for testing both asymptomatic and symptomatic persons, especially as recent studies described up to 46% of false positivity of antigen tests.1Hong K.H. Lee S.W. Kim T.S. Huh H.J. Lee J. Kim S.Y. et al.Guidelines for laboratory diagnosis of coronavirus disease 2019 (COVID-19) in Korea.Ann Lab Med. 2020; 40: 351‑60Crossref Scopus (264) Google Scholar, 2Zou L. Ruan F. Huang M. Liang L. Huang H. Hong Z. et al.SARS-CoV-2 viral load in upper respiratory specimens of infected patients.N Engl J Med. 2020; 382: 1177‑9Crossref Scopus (3423) Google Scholar, 3Kretschmer A. Kossow A. Grüne B. Schildgen O. Mathes T. Schildgen V. False positive rapid antigen tests for SARS-CoV-2 in the real-world and their economic burden.J Infect. 2021; 163 (4453(21)): 00402-00403Google Scholar If NPS were performed by medical staff at the beginning of the pandemic, they were rapidly passed on to other providers, sometime without any specific training or past experience. This enabled widescale upscaling with the retrieval of larger number of samples, but the absence of specific training for samplers raised the issue of sample quality and patients' acceptance and comfort during swabbing. Incorrectly performed, NPS can result in false negatives, therefore missing positive patients and detrimentally impacting on the pandemic,4Ai T. Yang Z. Hou H. Zhan C. Chen C. Lv W. et al.Correlation of chest CT and RT-PCR testing in coronavirus disease 2019 (COVID-19) in China: a report of 1014 cases.Radiology. 2020; 296 (Aug): E32-E40Crossref PubMed Scopus (3885) Google Scholar Furthermore, several oto-rhino-laryngological injuries have been reported, including osteo-meningeal breaches with cerebrospinal fluid leaks.5Paquin R. Ryan L. Vale F.L. Rutkowski M. Byrd JK. CSF leak after COVID-19 nasopharyngeal swab: a case report.Laryngoscope. 2021; 131 (9): 1927-1929https://doi.org/10.1002/lary.29462Crossref Scopus (24) Google Scholar Thus, poorly implemented swabbing and insufficient anatomical knowledge could have prejudicial consequences for patients and public health.6De Luca L. Maltoni S. Is naso-pharyngeal swab always safe for SARS-CoV-2 testing? An unusual, accidental foreign body swallowing.Clin J Gastroenterol. 2021; 14: 44‑7Crossref Scopus (13) Google Scholar Therefore, all studies and initiatives aimed at improving the efficiency of tests, making them more fluid and limiting the number of false negative/positive cases are more than welcome. For instance, Li et al. described a very interesting Integrated Mobile Container PCR Laboratory (IMCPL), aimed at reducing unnecessary rapid antigen testing.7Li M., Zhao J., Zang H., Fan X., Bai X., Integrated LuZ mobile container PCR laboratory (IMCPL): a novel strategy to reduce unnecessary rapid antigen testing. Published:September 15, 2021. DOI:10.1016/j.jinf.2021.09.008.Google Scholar Their IMPCL is a "standard PCR laboratory established inside a walk-in container and can be quickly set up at any convenient locations to carry out the large-scale diagnostic testing". Similarly, our own initiative in this field is a nasopharyngeal sample collection simulator (NP-SC), which we designed using a 3D printer, to optimize sample quality and decrease procedure-related discomfort. It was created to train professional samplers to safely perform NPS with the least discomfort for patients, aiming at an optimal swabbing of the area with the highest viral concentration. The aim of this study was to solicit opinions on our simulator from professional samplers from different in testing centers, regarding the realism and utility of this simulator for learning and perfecting NPS. This nasopharyngeal swab collection (NP-SC) simulator was designed by BONE 3D (Paris, France). A presentation video is freely available online: https://landing.bone3d.com/np-swab-simulator, as well as comprehensive 3D files and full instructions for manufacturing models.8Sananès N. Lodi M. Koch A. Lecointre L. Sananès A. Lefebvre N. et al.3D-printed simulator for nasopharyngeal swab collection for COVID-19.Eur Arch Oto-Rhino-Laryngol Off J Eur Fed Oto-Rhino-Laryngol Soc EUFOS Affil Ger Soc Oto-Rhino-Laryngol - Head Neck Surg. 2020; 278: 2649-2651Google Scholar A swabbing target on the posterior wall of the nasopharynx colors the swab tip if correctly inserted. The simulators were distributed to different laboratories (one per center). Experts professionals samplers from each laboratory, who had carried out >50 NPS, tested the device and provided a written evaluation through a questionnaire, divided into three parts:•Their swabbing experience and their opinion regarding the utility of the simulator.•The simulator modeling, relevance and use.•Experience acquired with the use of such simulator. All data collected were processed anonymously. The questionnaire included a form in which participants confirmed that they had no objection to data collection. The study was registered with the French National Commission for Information Technology and Civil Liberties (CNIL No. 2221408). This multicentric study was performed from October to December 2020 in 40 certified COVID-19-sampling laboratories. The NP-SC simulator was widely appreciated by its users, with a good overall rating of 7.9/10: 95% of users (38/40) found it easy to use and 85% (n = 34/40) thought it was realistic. Testers considered that this simulator had genuine utility for educational purposes (87.5%, 35/40) and 73.7% (28/38) thought that use of this simulator could improve their sampling technique. Additionally, 95% (38/40) reported that the device made the nasopharyngeal ducts anatomy easier to understand and 82% (32/39) estimated that the simulator, providing an in-real time visualization of the swab progression through the nasal cavity fossa, enabled a better understanding of how it was possible to go "off track", therefore improving patients' safety during sampling. The coloring of the swab tip upon correct insertion provided users with in-real-time visual feedback regarding their sampling quality. Therefore, 52.5% (21/40) thought the simulator improved their sampling technique and that their samples would now be more reliable (Fig. 1). Despite having previous swabbing experience (> 50 NPS), nearly half of the testers (18/40) felt more confident after training with the simulator. With increasing numbers of COVID-19 cases worldwide, NPS sampling has now become a routine procedure, with more than 1 million RT-qPCR tests carried out monthly in the US. Correct sampling is essential to limit false-negative cases, mostly related to poorly-performed NPS. In addition to being a financial burden, NPS are also not risk-free, especially for unexperienced samplers. Francesca et al.,9Francesca B.N. Barbara P. Emanuele F. Francesco S.C. Giovanni C. Fabio M. et al.Could a mannequin simplify rhinopharyngeal swab collection in COVID 19 patients?.Eur Arch Oto-Rhino-Laryngol Off J Eur Fed Oto-Rhino-Laryngol Soc EUFOS Affil Ger Soc Oto-Rhino-Laryngol - Head Neck Surg. 2020; 277: 2947‑8Google Scholar highlighted the need for NPS-training on mannequins, resulting in improved swabbing technique and increased comfort for patients. Therefore, we developed a 3D-printed nasopharyngeal sample simulator, to train professional samplers perform NPS under the safest possible conditions, with the least discomfort for patients aiming at an optimal swabbing of the area with the highest viral concentration. The simulator, available free-of-charge online, is made of a single rigid material, which enables highly-realistic and easy printing at low costs by NPS-performers all around the world. Experts professional samplers, performing dozens of tests day, widely acclaimed the device, judging it easy-to use (95%), realistic (85%) and anatomically-accurate (95%). It also had genuine utility for educational purposes, making the anatomy of the nasopharyngeal ducts easier to understand for novice samplers and illustrates the possibilities of going "off track", which is known to be at risk of causing pain/discomfort and may cause various injuries.4Ai T. Yang Z. Hou H. Zhan C. Chen C. Lv W. et al.Correlation of chest CT and RT-PCR testing in coronavirus disease 2019 (COVID-19) in China: a report of 1014 cases.Radiology. 2020; 296 (Aug): E32-E40Crossref PubMed Scopus (3885) Google Scholar In a similar way as several others initiatives (e.g., the IMCPL) our simulator aims at improving the cost-effectiveness ratio of tests, by reducing NPS-related morbidity as well as the number of false positives/negatives cases through improved practice. Judged realistic and easy-to-use by testers, this simulator, available online for free, can be manufactured on a non-professional 3D printer and appears as a very promising educational tool, especially for novice samplers. None. The simulators were funded by the Strasbourg University Foundation. This work was partially supported by French state funds managed within the "Plan Investissements d'Avenir" and by the ANR (reference ANR-10-IAHU-02) as Dr Lecointre and Venkatasamy are employees of the IHU.