Low-Cost Polyester-Tipped Three-Dimensionally Printed Nasopharyngeal Swab for the Detection of Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV-2)

Abstract

Case identification, isolation and contact tracing are fundamental strategies used to control the spread of Coronavirus Disease 2019 (COVID-19). This has led to widespread testing that resulted in the interruption of the supply chain for testing materials around the world. A prospective study was conducted to compare cheap and easily sourced 3-dimensionally printed polylactic acid and polyester nasopharyngeal swabs to commercially manufactured swabs, in detecting severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). During the study period, 287 laboratory-confirmed hospitalized COVID-19 patients, at multiple stages of their illness, were enrolled. The median age for the study population was 47.6 years (IQR: 34.4-56.6 years) and two-thirds (67.6%) of the subjects were male. The median duration of hospitalization, at the time of sampling, was 13 days (IQR 10-16 days). Overall concordance between the prototype and control swabs was 80.8% (Cohen's kappa coefficient = 0.61). Most discrepant results were due to prototype-positive control-negative results. When considering all positive results to be true positives, the prototype swab had a higher sensitivity (90.6% vs 80.8%, 95%CI 85.7-94.0% and 74.7-85.7%, respectively, p < 0.015). The cost to produce the prototype swab was estimated to be 0.05 USD per swab. Polylactic acid 3D-printed polyester-tipped swabs were shown to be effective for nasopharyngeal sample collection. We believe that this design can easily be adopted in countries where commercial swabs are not readily available and can play a vital role in public health efforts for disease control in low-income countries.

Practical strategies for SARS-CoV-2 RT-PCR testing in resource-constrained settings

“…In our limited testing, the prototype 3D-printed NMT lattice swabs showed high categorical concordance with NP swabs and also yielded similar viral loads compared to flocked NMT swabs. Similar high concordance has been demonstrated for 3Dprinted nasopharyngeal swabs [18][19][20]. Anecdotally, the prototype 3D-printed were observed to be more uncomfortable for study participants compared to flocked NMT swabs, a sentiment shared by other studies [18].…”

“…3D-printed plastic swabs may also help address supply chain shortages [18, 19]. We first acquired prototype NMT lattice swabs from Resolution Medical in anticipation of shortage of supplies for our research study.…”

Accessioning and automation compatible anterior nares swab design

“…In an effort to meet the dramatic increase in demand for nasal swabs, several groups have designed and 3D printed new swabs ( Alghounaim et al, 2020 ; Callahan et al, 2020 ). The performance of these swabs is comparable to that of standard swabs; however, they aim to reproduce the existing status quo, rather than to address some of the limitations caused by the standard swab design.…”

Innovative Design of 3D-Printed Nasopharyngeal Pediatric Swab for COVID-19 Detection

“…Detection of SARS-CoV-2 on respiratory specimens collected by nasopharyngeal (NP) swabs is the common modality for sample collection and subsequent SARS-CoV-2 detection by reverse transcription polymerase chain reaction (RT-PCR) [12]. To combat the global de cit of commercial (NP) swabs, 3dimentionally (3D)-printed NP swabs have been created and clinically validated as an alternative to the standard NP swab [13,14]. However, the majority of 3D-printed NP swabs are designed for adults, which can be too rigid and large for safe pediatric use [15].…”