A new sample preparation method to detect SARS-CoV-2 has been developed by scientists at Clinical Center (CC), the US National Eye Institute (NEI), and the National Institute of Dental and Craniofacial Research (NIDCR) at the National Institutes of Health (NIH), US. As per the study, titled, Sensitive Extraction-free SARS-Cov-2 RNA Virus Detection using a Chelating Resin, published in August 2021 in the journal iScience, the new method bypasses extraction of the virus’ genetic RNA material, and reduces test time and cost considerably. So, it is faster than the standard tests, which involve amplifying viral RNA to detectable levels using a technique—quantitative reverse transcription–polymerase chain reaction (RT-qPCR)—for which the RNA must be extracted from the sample.
Apart from being faster and cheaper, the new method stabilises the RNA at room temperature for easier transport, storage, and handling in clinical settings.
As per lead author, Bin Guan, from the US National Eye Institute (NEI), nasopharyngeal and saliva samples with various virion concentrations were used to analyse their reliability for direct RNA detection. It was found that they are reliable with markedly high sensitivity. The agent known as ‘Chelex 100 resin’ was used to preserve SARS-CoV-2 RNA in samples for detection by RT-qPcR. This preparation also inactivated the virus, making it safer for lab personnel to handle positive samples.
The scientists tested a variety of chemicals using synthetic and human samples to identify those that could preserve the RNA in samples with minimal degradation while allowing direct detection of the virus by RT-qPCR. The collected patient samples were stored in either viral transport media or the newly developed chelating-resin-buffer at the NIH Symptomatic Testing Facility to validate the test.
This discovery will prove to be quite beneficial and time-saving by enabling more tests to be conducted even without the need of extracting the virus’ genetic RNA material.
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