It wasn’t changed. The author is trying to suggest that the CDC was previously trying to perform genomic sequencing on samples with CT’s greater than 28. He then talks about how testing has been done yielding CT’s greater, 40ish. Yes, there have been tests that yielded low viral loads, but Tyler Durden never provided links to where the CDC was requesting higher CT’s be sent in for genomic sequencing. The CDC gives their explanation for requesting low CT (high viral load samples) to be sent in is because “high CT samples aren’t feasible for sequencing. “. They’re doing more sequencing now because the Biden admin increased funding for it in order to track the mutations.
In searching for confirmation, I stumbled across the following information which predates the pandemic and is in regards to viral testing in hogs, but their findings make sense when looking at the current CDC request:
“It was shown that samples with a CT less than 30 had a very high ORF5 sequencing success rate (99.85%).
Samples with CT from 30-32 still had over 90% sequencing success rate (92.80%).
For samples with Ct 32-34, the ORF5 sequencing success rates were 81.79%.
However, when the Ct values of the samples increased over 34, the ORF5 sequencing success rate decreased dramatically (58.92% for samples with Ct 34-36 and 40% for samples with Ct 36-37).”
https://www.nationalhogfarmer.com/health/prrsv-sequencing-success-dependent-upon-cycle-threshold-values