– Cheaper Covid-19 test more efficient than PCR in detecting alpha variants

May 06, 2022

A new point-of-care Covid test has proven successful in distinguishing the alpha variant from previous strains.

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The new test builds on previous developments by University of Illinois Urbana-Champaign researchers, where samples could bypass the lab — first with nasopharyngeal swabs, then with saliva samples.

The point-of-care amplification and testing process, called LAMP, is more efficient than PCR because it does not require expensive thermocycling machines. The researchers said the assay does not require RNA extraction and purification steps, similar to the Illinois saliva test.

“Our study shows that it is possible to test for variants of the same strain of coronavirus using a handheld wearable device in a single point-of-care test lasting 30 minutes,” Bashir said.

“The new test is scalable for future pandemics, COVID-19 or otherwise, and could be used at home or in other settings.”
The updated process uses a genetic phenomenon called S gene target failure – which is present in the alpha variant but not in the early strains of the SARS-CoV-2 virus – to distinguish between the two alpha variants, they said the explorers.

“The new omicron variant also exhibits an S gene target failure and could be tested by adapting the approach developed in this study,” said Valera.

During the new testing procedure, specially selected genetic primers are applied to additively manufactured cartridges and dried before patient samples are added. The chosen primers are set against the S gene and are specific for detecting S gene target failure against 69-70 deletion in the alpha variant, the study reports.

The study confirmed the effectiveness of the device by testing 38 clinical saliva samples, including 20 samples that tested positive for the alpha variant.

The researchers said they would like to refine their method to test up to five different viruses, viral strains and variants in a single test compatible with a nasal swab and saliva media.

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