3D Printed Nasal Swabs as Effective as Flocked Swabs in Diagnosing COVID-19

One of the biggest challenges during the COVID-19 pandemic has been whether facilities have enough supplies to conduct the nasopharyngeal (NP) tests for diagnosis. The University of South Florida (USF) radiology department has a solution to this problem – 3D printed NP swabs.

USF researchers, led by Summer Decker, Ph.D., associate professor, vice chair for research, and director of the radiology department’s 3D Clinical Applications, immediately recognized at the beginning of the pandemic that there would be a need for more swabs. Using their 3D printer, they built the swabs and ran a clinical trial.

Their swabs have already received national and international recognition for applying 3D medical printing power in a novel way to create an innovative clinical solution. The results of this first clinical trial will be presented during the Radiological Society of North America (RSNA) annual meeting next week.

“To date, USF Health has printed more than 100,000 3D NP swabs, and hospitals around the world have used our 3D files to print tens of millions more swabs for point-of-care use,” Decker explained. 

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Largely, providers worldwide are using a flocked NP swab that contains a narrow plastic rod and a tip covered in a flocked polyester material to collect nasal secretion samples from the back of the nose and throat. It is considered the current standard of care for lab analysis and COVID-19 diagnosis. As the pandemic has raged on, however, supplies have become scarce in many areas.

To address the need, Decker’s team created interdisciplinary partnerships that were born out of the RSNA 3D Printing Special Interest group. The project, she said, highlights the unique ways radiology departments can impact hospitals and clinical care during global crises.

“We collaborated with our colleagues in infectious disease, virology, emergency medicine, and radiology, as well as Todd Goldstein, Ph.D., at Northwell Health System’s 3D Design and Innovation Lab in New York City. The city was the U.S. epicenter of virus infection at the time,” she said. “In a matter of days, we came up with 12 designs and printed three to test on ourselves.”

Using FormLabs printers and surgical grade resin, Decker’s team developed their final prototype and submitted it to infectious disease specialists at both USF and Northwell for validation testing, ensuring the swab could gather enough viral cells and hold them for up to three days. They also needed to ensure the resin would not interfere with test results.

For the clinical trial, the USF team tested the swab at numerous clinical sites, including Tampa General Hospital, Northwell Hospital, and Thomas Jefferson University Hospital in Philadelphia. At those three sites, they tested 291 patients, between ages 14 to 94, who were either hospitalized or seen in the emergency department with both the flocked and 3D-printed swabs.

The results, Decker said, were statistically identical in a head-to-head trial.

“The results were overwhelmingly positive,” she said. “The clinical trial showed that the 3D nasal swabs performed as well as – or, in some cases, better than – flocked swabs.”

As a result, Tampa General Hospital has changed its standard of care, adopting the 3D swabs and printing more than 300 swabs a day for both the hospital and its affiliated care centers. All total, the hospital’s six printers can produce 9,000 swabs each week.

The printing process lasts roughly 15 hours, during which the printed swabs are rinsed in isopropyl alcohol, cured, and hand inspected for defects. Infectious disease experts also examine the swabs before they are sterilized in an autoclave and packed into a test kit.

While USF has filed a provisional patent on the 3D NP swab, it has made the design files and clinical data available to hospitals, clinics, and licensed medical device companies around the world at no cost.

“We wanted to get this swab in as many hands as possible to help slow the spread of the virus,” Decker said. “This is the resultl of many people working together to make one device to help others.”

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