But could focusing so much on achieving the greatest molecular sensitivity for asymptomatic testing *when testing is infrequent* be doing more harm than good?
I’ll explain
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Like detecting DNA in a piece of hair, detecting virus RNA tells little about whether the virus is still active...
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So ultimately, the majority of time spent in the PCR positive state is after infection, not transmissible
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The idea of the super sensitive PCR test is to detect people when at low viral load at the beginning of infxn
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But this can be bad - it leads to unnecessary quarantines of people already past their infection
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So in the US we are unnecessarily quarantining millions of ppl, assuming they are infected when they’re already recovered
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What we gain is ability to find someone a few hours earlier - only IF by chance the swab is taken in the few hours where it makes a difference
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Further, we mistakenly end up quarantining millions of ppl for 10d bc we erroneously assume any PCR + test was collected at the beginning of an infection. When most are after.
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The apparent missed cases maybe aren’t false negatives. Maybe the (+) on the PCR are False (+) for actionable results
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Maybe less sensitive is better for some things.
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But it’s not always better & sometimes a lower sensitivity test is more accurate at detecting active infection.
“To Interpret the SARS-CoV-2 year, consider the Cycle Threshold Value”
academic.oup.com/cid/advance-ar…