NIH Scientists Develop Covid-19 Test Faster Than RT-PCR

The method is the result of a collaboration between researchers from the US National Eye Institute (NEI), the NIH Clinical Center (CC) and the National Institute for Dental and Craniofacial Research (NIDCR).

Standard tests involve amplifying viral RNA to detectable levels using a technique called RT-qPCR. But first, the RNA must be extracted from the sample. Manufacturers of RNA extraction kits have struggled to keep up with demand during the pandemic.

The researchers used an agent made by laboratory supply company Bio-Rad called “Chelex 100 resin” to preserve SARS-CoV-2 RNA in samples to be detected by RT-qPCR.

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“We used nasopharyngeal and saliva samples with different concentrations of virions to assess whether they could be used for direct detection of RNA. The answer was yes, with markedly high sensitivity. In addition, this preparation has inactivated the virus, which allows laboratory personnel to handle positive samples safely, ”said NIH, citing lead author Bin Guan, of the US National Eye Institute. The article was published in iScience.

The team made their discovery by testing a variety of chemicals using synthetic and human samples to identify those that could preserve RNA in samples with minimal degradation while still allowing direct detection of the virus by RT. -qPCR.

To validate the test, they collected patient samples and stored them either in viral transport medium or in the newly developed chelating resin buffer at the NIH Symptomatic Testing Facility.

Samples in viral transport media were tested by the Covid-19 testing team at the NIH Clinical Center, using conventional RNA extraction and RT-qPCR assays. The samples in the chelating resin buffer were heated and the viral RNA was then tested by RT-qPCR. The new preparation significantly increased the yield of RNA available for testing, compared to the standard method. –Source: NIH (United States)