IRP scientists develop faster COVID-19 test

Monday, August 16, 2021

Scientists at the National Institutes of Health (NIH) have developed a new sample preparation method to detect SARS-Cov-2, the virus that causes COVID-19. The method bypasses extraction of the virus’ genetic RNA material, simplifying sample purification and potentially reducing test time and cost. The method is the result of a collaboration among researchers at the National Eye Institute (NEI), the NIH Clinical Center (CC), and the National Institute of Dental and Craniofacial Research (NIDCR).

Diagnostic testing remains a crucial tool in the fight against the COVID-19 pandemic. Standard tests for detection of SARS-CoV-2 involve amplifying viral RNA to detectable levels using a technique called quantitative reverse transcription PCR (RT-qPCR). But first, the RNA must be extracted from the sample. Manufacturers of RNA extraction kits have had difficulty keeping up with demand during the COVID-19 pandemic, hindering testing capacity worldwide. With new virus variants emerging, the need for better, faster tests is greater than ever.

A team led by Robert B. Hufnagel, M.D., Ph.D., chief of the NEI Medical Genetics and Ophthalmic Genomic Unit, and Bin Guan, Ph.D., a fellow at the Ophthalmic Genomics Laboratory at NEI, used a chelating agent made by the lab supply company Bio-Rad called Chelex 100 resin to preserve SARS-CoV-2 RNA in samples for detection by RT-qPCR.

“We used nasopharyngeal and saliva samples with various virion concentrations to evaluate whether they could be used for direct RNA detection,” said Guan, the lead author of a report on the technique, which published this week in iScience. “The answer was yes, with markedly high sensitivity. Also, this preparation inactivated the virus, making it safer for lab personnel to handle positive samples.”