The presence of only a few pathogens in a sample will either not result in a positive test or will require a very large number of cycles to give a positive. That is why there are guidelines on how many cycles are run for a real infection. Beyond that number the result is considered an artifact and not valid.
The assay eliminates the human response to whatever is present. The human response is either illness or health. Presence doesn’t mean ‘illness’ by any definition. This assay was to identify pathogens present in too few a number to be identified by other means.
The CDC had the PCR test, which was not based on the COvid virus, but on a ‘related corona virus’ run at 40 cycles until the ‘vaccine’ was released, and then it had the C19 PCR test run at 25 cycles for the unvaccinated only. The vaccinated continued to have their PCR’s run at 40 cycles (meaningless results).