Researchers have developed 3D-printed nasopharyngeal (NP) swabs using a point-of-care 3D printer in response to the critical shortage of NP swabs for COVID-19 testing.

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"To date, we have 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," said study author Summer Decker from University of South Florida in the US. The 3D swab has received national and international recognition as an example of the power of medical 3D printing and quick innovation to provide clinical solutions.

The flocked NP swab, which collects a test sample of nasal secretions from the back of the nose and throat for lab analysis, is the current standard of care for diagnosing COVID-19. It consists of a narrow plastic rod and a tip covered in a flocked polyester material. "COVID-19 appears first in the nasopharyngeal regions and from there it's inhaled into the respiratory system," Decker explained.

The final prototype, developed using FormLabs printers and surgical grade resin, was sent to infectious disease specialists for validation testing. "We needed to determine that the 3D NP swab could gather enough viral cells and hold them for up to three days, and that the resin would not interfere with test results," she said. To compare the performance of the 3D NP swab with the flocked swab, the team initiated a clinical trial at numerous sites. At the three trial sites, 291 patients (ages 14-94) who were hospitalized or seen in the emergency room were tested for COVID-19 using both the flocked swab and 3D swab.

The 3D swab displayed statistically identical results to the flocked swab in the head-to-head trial. "The results were overwhelmingly positive. The clinical trial showed that the 3D nasal swabs performed as well as - or, in some cases, better than - flocked swabs," Decker noted.