Development and Implementation of an At-Home COVID-19 Mid-Turbinate Test Applicator

Kathleen Fallon, Noah Ashley, Julia Thompson, Annie Messing

Abstract

The spread of COVID-19 throughout the US has demonstrated a great need for widespread, accurate testing. Currently, a large problem facing healthcare providers is the high percentage of false negatives. In this project, we have designed an applicator for the mid-turbinate COVID-19 test that aims to standardize the testing process and reduce false negatives.

We designed an applicator that has a size and shape similar to a pen. Using a spring mechanism, the swab is pushed into the nose until it reaches the middle turbinate. It then rotates through a helical track to collect specimens from all sides of the nasal wall. Upon removal, the swab retracts into the nose cone and a cap is placed on the cone to preserve sterility and protect the sample.

We anticipate a decreased percentage of false negatives as our applicator removes the guesswork from obtaining samples. This also allows for increased at-home testing because clinicians are not needed to perform the test. We are currently 3D printing this device and will begin testing soon. The end goal of this project is to incorporate the applicator into at-home test kits and into Clemson’s voluntary testing program this fall. 

Introduction

Accurate and widespread testing for COVID-19 is crucial to help treat and isolate infected individuals, an important step in containing the spread. Hospitals and testing centers commonly use nasopharyngeal (NP), oropharyngeal (OP), nasal mid-turbinate, or anterior nares (nasal) swabs to test for SARS-CoV-2, the virus that causes COVID-19. 

Excessive false negatives remain a persistent problem faced by healthcare providers. Our applicator design provides a standardized procedure for specimen collection, limiting incorrect results due to user error. Additionally, due to the demand for testing, long wait times at testing centers is a persistent issue. Preliminary studies have demonstrated that mid-turbinate at-home sample collection has an accuracy rate of 96.2% when compared to healthcare provider administration of a nasopharyngeal swab (Tu et. al). Our applicator limits the need for healthcare providers and in-person testing, reducing the burden on overwhelmed test centers and hospitals and decreasing the wait time.

Materials and Methods

Due to the novelty of COVID-19, substantial research has not been done on the accuracy of various tests for this virus. Flu tests are performed similarly, so we used research from those tests as a basis for our project. The 1cm tests were shown to be significantly less sensitive to the flu virus than the mid-turbinate tests, with a much higher rate of false negatives. However, there was only a 2% sensitivity difference between the mid-turbinate test and the nasopharyngeal test (Frazee et. al). Given the fact that the nasopharyngeal test is much more uncomfortable and nearly impossible to perform without a clinician present, we decided to focus on the mid-turbinate test.

The CDC guidelines recommend that the swab is rotated three times once it has reached the mid turbinate (“Information for Laboratories”). Because of this, we designed our prototype to perform three rotations while in the nose. It is important that these rotations occur once the mid-turbinate is reached, so the swab follows a straight path until it reaches the mid turbinate, and then the rotation begins.

Due to the intricacy of the design, we decided to model the applicator using Solidworks and 3D print the finished product. We spoke with 3D printing experts in Clemson Machining and Technical Services, and given the small scale of the prototype, they suggested that the HP printer in Nylon would allow for the most accurate and detailed printing of our device.

Results

Knowing that variation in testing is a large issue in the COVID pandemic, we focused on standardizing the testing process as much as possible. Therefore, we found that a mechanism similar to a pen click would limit potential user error of our device by automating the applicator.

Our device is composed of seven pieces. They include a spring and six 3D printed parts: the nose cone, the housing, the plunger, the stage, the upper cam and the lower cam. The nasal swab sits inside our device in the stage, which has an extrusion on the side that follows a track cut out of the inside of the housing. This track allows for linear travel to insert the swab into the nose, followed by rotational motion of the swab to collect a better sample. To begin the test, the user places the nose cone in one nostril. The nose cone will properly align the device in the nose. The user then depresses the plunger, which propels the stage forward, extending the swab and compressing the spring inside. Once the plunger has been fully depressed, the upper cam rotates to hold the swab in its extended position, and a “click” sound can be heard, signaling the swab is fully inserted into the nose. A second depression of the plunger causes the upper cam to rotate back into its original position and retract the swab into the housing. The device can then be removed from the nostril, and the swab is protected from outside contaminants.

Our first 3D print of the device was successful, and all the parts printed without any major issues. However, after assembling the pieces, there are several changes that need to be made to the device in order for it to function as designed. The tolerances throughout the model need to be increased to allow for fewer interferences between moving pieces. In addition, the extrusion on the stage will be enlarged to allow for easier rotation of the swab. Our next iteration will also include a feature to prevent the plunger from falling out of the housing. Lastly, the nose cone will be sized down and narrowed to fit more comfortably in the nostril.

Conclusions

The COVID-19 pandemic has stretched and challenged our healthcare systems in ways never seen before. We believe that this mid-turbinate applicator will alleviate some of these burdens for both clinicians and processing technicians. Our current prototype allows for less false negatives by creating a uniform testing procedure and sterile transport environment. 

Moving forward, we hope to refine our prototype by making it shorter and improving the clicking mechanism to increase patient compliance. Furthermore, we will seek additional guidance from FDA and CDC guidelines as they are released and will gather feedback from testers. Eventually, we hope to include this applicator in an at-home testing kit for universities and employers. Using these testing kits, we can create safer work and school environments post-pandemic.

References

Frazee, B. W., Rodríguez-Hoces de la Guardia, A., Alter, H., Chen, C. G., Fuentes, E. L., Holzer, A. K., Lolas, M., Mitra, D., Vohra, J., & Dekker, C. L. (in press). Accuracy and Discomfort of Different Types of Intranasal Specimen Collection Methods for Molecular Influenza Testing in Emergency Department Patients. Annals of Emergency Medicine.

Information for Laboratories about Coronavirus (COVID-19). (2020, February 11). Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/lab/guidelines-clinical-specimens.html

Logan, Sarah. (2019). Nose Anatomy [jpeg]. Ress ENT. http://www.ress-ent.com/2019/03/what-to-expect-during-turbinate-reduction-surgery/

Tu, Y.-P., Jennings, R., Hart, B., Cangelosi, G., Wood, R., Wehber, K., Verma, P., Vojta, D., & Berke, E. M. (in press). Patient-collected tongue, nasal, and mid-turbinate swabs for SARS-CoV-2 yield equivalent sensitivity to health care worker collected nasopharyngeal swabs. Patient-Collected Tongue, Nasal, and Mid-Turbinate Swabs for SARS-CoV-2 Yield Equivalent Sensitivity to Health Care Worker Collected Nasopharyngeal Swabs.

Acknowledgements

We would like to thank Dr. John DesJardins of Clemson Bioengineering, Belinda Cochran of AnMed Health Medical Center, and Prisma Health Upstate for their contributions and assistance during this research.