Rapid and Simple COVID-19 Assay Allows Variant Identification
SARS-COV-2 ASSAYS have become an integral part of the world’s recovery from the COVID-19 pandemic. Recent evidence has emerged revealing that a new real-time PCR (RT-PCR) test from Seegene Technologies (Walnut Creek, California, USA) is able to accurately identify multiple variants of COVID-19, and is comparable to the current gold standard Sanger (Sanger, California, USA) testing, which uses assays to detect the viral spike protein.
Known as the Novaplex SARS-CoV-2 Variant I, II, and IV RT-PCR assays, this novel testing technique detects the genetic mutations present in the alpha, beta, delta, and epsilon variants in a rapid and simple way, providing more accurate results. The study, led by Ping Ren, Department of Pathology, University of Texas Medical Branch, USA, tested each sample using the Novaplex assays and Sanger sequencing following RNA extraction. The scientists also tested each sample directly without Novaplex RNA extraction.
The study tested 156 samples that had undergone RNA extraction, of which the RT-PCR assays identified 109 different variants; this result was in 100% agreement with the Sanger method. The method that did not use extracted RNA was 91.7% as sensitive as the alternative; however, in samples with a lower viral load, these assays failed to identify some genetic mutations. The scientists concluded that this was due to low nucleic acid concentrations in the samples.
The co-lead author, Marisa C. Nielsen, Department of Pathology, University of Texas Medical Branch, explained how a major limiting factor of SARS-CoV-2 testing was the limited availability of RNA extraction reagents, as conventional extraction is time-consuming. Nielsen continued: “Although lower sensitivity was observed with the extraction-free method, it still represents a viable alternative.”
Additional variants can be detected through the development of accessible RT-PCR tests that include genes to represent new variants, which will be greatly informative to public health. Ren stated: “Determining the SARS-CoV-2 variant in individual patient samples can help guide treatment since some variants are more resistant to current treatment regimens… It is important to track variant spread as part of public health surveillance because of variant-dependent transmission, disease severity, and treatment decisions.”