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PCR tests have very low false positives. If you've got a tiny spec whatever genetic material the machine is set to amplify... it will happily do so. The intent
by spookthesunset 6y ago
PCR tests have very low false positives. If you've got a tiny spec whatever genetic material the machine is set to amplify... it will happily do so.
The intent of covid tests isn't to see if you have a tiny insignificant spec of SARS-CoV-2 in your nasal passage. The intent is to see if you have Covid19 and are possibly contagious. When you amplify too much, you are defeating the purpose of the test. A tiny spec of remnant SARS-CoV-2 doesn't mean you are contagious or have Covid19. It just means you have a tiny spec of viral material up in your nose.
- sobriquet9 6y agoThat's why COVID-19 is diagnosed not only by rt-PCR, but also on the basis of symptoms, chest CT scans, and other nucleic acid testing.
- cameldrv 6y agoThe problem is that you may be in an early stage of infection where there isn't much virus, or the swab may not have caught much of it. You could also have already recovered from an asymptomatic infection, and there is some residual viral RNA. A high Ct could be because of one of those factors, or from cross-contamination.