Saliva testing at MUSC: Screening for COVID just got less invasive, safer

What once seemed like a dream is now a reality at MUSC Health. Instead of a swab up the nose, patients now may be able to test for COVID-19 by simply spitting in a tube.

Thanks to the hard work of two teams, MUSC is ready to roll out saliva testing this week. Satish Nadig, M.D., D.Phil., and Vamsi Gangaraju, Ph.D., have led the team focused on using research lab equipment, while Rasesh Parikh, Ph.D., a staff scientist in Gangaraju’s lab, was the boots on the ground on the research lab side, playing an instrumental role in setting up saliva testing.

Julie Hirschhorn, Ph.D., and Steven Carroll, M.D., have been at the helm of the team concentrating on the high-output equipment from the clinical lab. Together, they leaned on extensive personnel working behind the scenes, including information services, supply chain experts, logistical consultants and project management.

“This was a big problem to solve, and it needed a lot of heads to come together and work together,” Gangaraju said. “The collaboration that has gone on with this has been amazing.”

Hirschhorn agreed. “Because the clinical labs and research labs are regulated in different ways, it isn’t always easy to work together. But because of how important it is for us to understand this coronavirus better, it brought us together in ways we previously never thought of. And the truth is that it was really nice to have fresh eyes on difficult specimen types.”

As for its reliability, the saliva test’s accuracy – or sensitivity as researchers and clinicians call it – is currently above 90%.

Besides the obvious benefits to the patient, there were several other reasons for developing a reliable saliva test. While the nasopharyngeal (NP) test goes deep into the nasal cavity and must be administered by a health care professional, the saliva test – because the patient can hold the tube and spit in it him- or herself – requires less PPE, not to mention less extensive training to collect. So not only is it easier on the patient, in theory, it is safer for the health care providers.

“It’s just a lot less invasive,” Nadig said. “Safer all around. It’s simple and effective.”

The transition from NP testing to saliva wasn’t something that happened overnight. The saliva tests at MUSC Health underwent a rigorous validation process before being made available to patients. This critical step demonstrates that it favorably compared to the “gold standard” NP swab tests used within the clinical laboratories at MUSC. High levels of accuracy were reported for the MUSC Health saliva test, thanks to the continued interdisciplinary collaboration and expertise-sharing among clinical care and bench research teams.

MUSC is planning to start saliva testing on symptomatic ambulatory patients in Charleston, followed by patients in Florence and Lancaster before slowly ramping it up for wider use. As availability becomes wider in the coming weeks, it will be rolled out to additional areas.

“We wouldn’t be using this method of testing if it weren’t accurate,” Carroll said. “Our top priority is always to protect our patients. If we’ve put it out there, we believe in it.”

As MUSC Health makes COVID-19 saliva testing more widely available, it is important to make sure individuals understand the details related to its use:

  • Saliva is much easier to collect for the patient and providers involved, so it provides another tool in the testing tool box.
  • NP swabbing and saliva-based testing will continue in parallel at MUSC and take about the same amount of time to process; one method does not replace another for all patients.
  • MUSC Health is pursuing point-of-care “rapid” saliva-based testing, but it is not available at this time.
  • PCR-based saliva testing is not necessarily faster in terms of time to process results within the lab, nor is it less expensive to process than NP swab testing.
  • Saliva testing might not be ideal for every patient in every situation. The SARS-CoV-2 virus replicates in the nasopharynx, which is why NP swabs are the gold standard. It does not replicate efficiently in the oral cavity, and therefore, the detection of the virus in saliva is most reliable during the acute phase of infection.

If there’s a silver lining to the pandemic, it’s that so many smart people have come together to work in new and innovative ways.

“We are going to take this collaboration and expand it going forward,” Carroll said. “We want to keep this kind of out-of-the-box thinking going so everybody doesn’t go back to their silos once this pandemic is over.”

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