“Making something out of nothing”: PCR tests, CT values and false positives. A comment on the efficacy of the RT-PCR test in view of the Jaafar paper.

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Niels Harrit PhD

SUMMARY: If inoculation can be used as verification of the Corman-Drosten RT-PCR test for Covid-19, about 50% of the positive results reported must be considered false when a maximum of 35 cycles are applied. If only 25 cycles are applied the fraction of false positives drops to 20%.

The efficacy of the RT-PCR test used to identify infection by the SARS-CoV-2 virus and ”cases” of the Covid-19 disease is widely disputed. In these discussions, it is often maintained that the test produces 97% false positives. Reference for that claim is made to a study by a Marseille-based group who communicated their results in a letter to the editor on September 28th, 2020.[1]

The first author is R. Jaafar, so it is hereafter referred to as the Jaafar-paper. It represents an expanded data set compared to an earlier study[2] spearheaded by B. La Scola. This publication is referred to as the La Scola-paper.

In sum, the reults presented in the Jaafar-paper do not provide stand-alone proof for the test producing 97% false positives. The present comment is an attempt to distill the essential conclusions from their data. Continue reading on