Is sample contamination more impactful (likely to lead to a false positive) at 100 or 200 cycles than at 20? I remember some distrust of high PCR cycle counts during COVID but I never quite understood the fear.
If there is contamination with the target sequence then it will be found by the PCR analysis. I don’t know the practical limits of sensitivity but theoretically it can detect a single occurrence of the target sequence.
With enough cycles, dead virus you're successfully fighting off can be detected. It doesn't need contamination. For what it was used for, those were false positives that inflated the counts.
