August 12, 2021 at 4:43 pm #1756AnonymousInactive
Though the whole world relies on RT-PCR to “diagnose” Sars-Cov-2 infection, the science is clear: they are not fit for purpose.
Torsten Engelbrecht and Konstantin Demete
Full article available here.
The MIQE guidelines have been developed under the aegis of Stephen A. Bustin, Professor of Molecular Medicine, a world-renowned expert on quantitative PCR and author of the book A-Z of Quantitative PCR which has been called “the bible of qPCR.”
In a previous podcast interview Bustin points out that “the use of such arbitrary Cq cut-offs is not ideal, because they may be either too low (eliminating valid results) or too high (increasing false “positive” results).” And, according to him, a Cq in the 20s to 30s should be aimed at and there is concern regarding the reliability of the results for any Cq over 35.
If the Cq value gets too high, it becomes difficult to distinguish real signal from background, for example due to reactions of primers and fluorescent probes, and hence there is a higher probability of false positives.
Moreover, among other factors that can alter the result, before starting with the actual PCR, in case you are looking for presumed RNA viruses such as SARS-CoV-2, the RNA must be converted to complementary DNA (cDNA) with the enzyme Reverse Transcriptase—hence the “RT” at the beginning of “PCR” or “qPCR.”
But this transformation process is “widely recognized as inefficient and variable,” as Jessica Schwaber from the Centre for Commercialization of Regenerative Medicine in Toronto and two research colleagues pointed out in a 2019 paper.
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