3 ms·

That figure seems questionable. 1) high cycle PCR tests tend to produce false positives. [0] 2) recently (maybe now?) the CDC was recommending that the cycle

That figure seems questionable. 1) high cycle PCR tests tend to produce false positives. [0] 2) recently (maybe now?) the CDC was recommending that the cycle count be lowered for vaccinated individuals (break through cases). [1] If unvaccinated individuals are being tested to a different standard, that would seem to muddy the waters, wouldn't it? [0] https://medicine.yale.edu/labmed/sections/virology/COVID-19%20Ct%20values_YNHH%20Aug.%202020%20_395430_36854_v1.pdf https://medicine.yale.edu/labmed/sections/virology/COVID-19%... [1] https://web.archive.org/web/20210623005911/https://www.cdc.gov/vaccines/covid-19/downloads/Information-for-laboratories-COVID-vaccine-breakthrough-case-investigation.pdf https://web.archive.org/web/20210623005911/https://www.cdc.g...

a_conservative 5y ago
I posted this comment in good faith. I would appreciate feedback rather than downvotes.
nullc 5y ago
I'm not the downvoters but: I followed your link [1] and read the entire page multiple times and I can find no content which supports "recommending that the cycle count be lowered for vaccinated individuals". It says that samples submitted for sequencing should be positive when CT<=28 or are detected as positive by another modality.
- a_conservative 5y ago
  I wish I could find a "slam dunk" source that stated what the current threshold recommended by the CDC, but I can't quite find it. I've personally read many sources that talked about using cycle counts above 30 over the past year. Some more discussion on this topic was on HN yesterday [0] also, from last August: One solution would be to adjust the cycle threshold used now to decide that a patient is infected. Most tests set the limit at 40, a few at 37. This means that you are positive for the coronavirus if the test process required up to 40 cycles, or 37, to detect the virus. [1] [0] https://news.ycombinator.com/item?id=27972195 https://news.ycombinator.com/item?id=27972195 [1] https://www.nytimes.com/2020/08/29/health/coronavirus-testing.html https://www.nytimes.com/2020/08/29/health/coronavirus-testin...

a_conservative 5y ago

I posted this comment in good faith. I would appreciate feedback rather than downvotes.

nullc 5y ago

I'm not the downvoters but: I followed your link [1] and read the entire page multiple times and I can find no content which supports "recommending that the cycle count be lowered for vaccinated individuals". It says that samples submitted for sequencing should be positive when CT<=28 or are detected as positive by another modality.

a_conservative 5y ago
I wish I could find a "slam dunk" source that stated what the current threshold recommended by the CDC, but I can't quite find it. I've personally read many sources that talked about using cycle counts above 30 over the past year. Some more discussion on this topic was on HN yesterday [0] also, from last August: One solution would be to adjust the cycle threshold used now to decide that a patient is infected. Most tests set the limit at 40, a few at 37. This means that you are positive for the coronavirus if the test process required up to 40 cycles, or 37, to detect the virus. [1] [0] https://news.ycombinator.com/item?id=27972195 https://news.ycombinator.com/item?id=27972195 [1] https://www.nytimes.com/2020/08/29/health/coronavirus-testing.html https://www.nytimes.com/2020/08/29/health/coronavirus-testin...