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Yale Extraction-Free SARS-CoV-2 Saliva Test Gets FDA Emergency Use Authorization

NEW YORK ─ The US Food and Drug Administration on Saturday said it has issued emergency use authorization to Yale School of Public Health for its SalivaDirect COVID-19 diagnostic test, which uses a new method of processing saliva samples being tested for SARS-CoV-2.

With SalivaDirect, a saliva sample can be collected in a sterile container, and the method does not require special types of swabs or collection devices, the FDA said. The method also does not require a separate nucleic acid extraction step, significant because extraction kits used for this step in other tests have been prone to shortages, the FDA noted.

SalivaDirect enables testing of low volumes of saliva using a dualplex RT-qPCR method for SARS-CoV-2 RNA detection. Saliva, first treated with proteinase K followed by a heat inactivation step, serves as the sample for the RT-qPCR test. The test uses validated primer and probe sets developed by the US Centers for Disease Control and Prevention.

Testing is limited to laboratories designated by the Yale School of Public Health, which include Yale School of Medicine's CLIA-certified Clinical Molecular Diagnostics Laboratory in New Haven, Connecticut. Additionally, the SalivaDirect method has been validated and authorized for use with different combinations of commonly used reagents and instruments, meaning the test could be used broadly in most high-complexity labs, the FDA said.

Yale intends to provide the SalivaDirect protocol freely to interested laboratories; designated laboratories could follow a specific protocol to obtain the required components and perform the test in their lab according to Yale's instructions for use.

"Providing this type of flexibility for processing saliva samples to test for COVID-19 infection is groundbreaking in terms of efficiency and avoiding shortages of crucial test components like reagents," FDA Commissioner Stephen Hahn said in a statement.

The FDA issued the first saliva test EUA to the Rutgers Clinical Genomics Laboratory at RUCDR Infinite Biologics in April. The FDA amended the Rutgers EUA in May to enable at-home collection.

It subsequently issued EUAs to saliva-based tests from Phosphorus Diagnostics in June and P23 Labs as well as Clinical Reference Laboratory in July.

Testing saliva eliminates the need for nasopharyngeal swabs, which have also been prone to shortages, and alleviates the patient discomfort associated with these swabs, the FDA noted. Since the saliva sample is self-collected under the observation of a healthcare professional, it could also potentially lower the risk posed to healthcare workers responsible for sample collection, the agency added.

The FDA noted that it has seen variable performance in tests using saliva, but it determined that SalivaDirect meets EUA criteria based on the data submitted by the Yale School of Public Health.

SalivaDirect is being further validated as a test for asymptomatic individuals through a program that tests players and staff from the National Basketball Association.