The PCR test is widely used to confirm Covid-19 infections, but does it actually work? The writer quotes the Nobel laureate who invented the PCR test, Karry Mullis, to answer this question:
PCR is intended to identify substances qualitatively, but by its very nature is unsuited for estimating numbers [of viruses]. Although there is a common misimpression that the viral load tests actually count the number of viruses in the blood, these tests cannot detect free, infectious viruses at all; they can only detect proteins that are believed, in some cases wrongly, to be unique to [the disease agent]. The tests can detect genetic sequences of viruses, but not viruses themselves.
I interpret this to mean that the PCR test may be an effective diagnostic tool for Covid-19 IF the protein it detects is in fact unique to SARS-Cov-2. There are two main issues in this: First, we must know that SARS-Cov-2 is real. Second, we must know that the protein the Covid PCR detects belongs to SARS-Cov-2 and to no other biological agent.