CDC finally specifying using lower CT thresholds for PCR tests, but only for the vaccinated

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Last August, the New York Times reported that so many PCR tests were netting false positives because they used more than 30 cycle thresholds (CTs) of amplification, often as many as 40-45 before finding a positive culture. To this day, the CDC has refused to change its guidance on the use of high CTs in determining positive results, needlessly forcing so many people, particularly asymptomatic children, into quarantine for no reason. Well, now the agency has finally changed its guidance — but only when it suits cronies.

In a notice on its “COVID-19 vaccine breakthrough case investigation,” the CDC announced its plan to study the prevalence of “breakthrough cases,” meaning those who contract the virus even after having been vaccinated. Yesterday, former New York Times reporter Alex Berenson noticed this little gem in the guidance for determining those infected post-vaccination: “Clinical specimens for sequencing should have an RT-PCR Ct value ≤28.”

Alas, the CDC has suddenly discovered the power of cycle thresholds on PCR testing in determining whether the positive results are real or meaningful. But here’s the problem: Where is this guidance when it comes to non-vaccinated people? As Berenson points out, a standard of 28 CTs applied to the general testing regime would preclude as many as 90% of cases from being recorded, especially when the virus is in low circulation.

Wow. WOW. @cdcgov only wants to examine post-vaccine infections with a PCR threshold of 28 or under. That standard…

— Alex Berenson (@Alex Berenson)1619716838.0

Almost eight months ago, the New York Times reported that cultures detected in 27 to 34 CTs seldom reveal any live virus, and specimens detected above 34 CTs never show any live virus. Most research shows that any virus that is detected only through a CT level above 25, and certainly above 30, is very likely to be a false or meaningless positive. This is why a Portuguese judge recently ruled that any positive test that used more than 25 cycle thresholds is not reliable and cannot be used to force quarantine.

Each cycle threshold doubles the level of amplification of the previous CT. Thus, a CT of 40 is 1,024 times the amplification of a CT level of 30 (210 =1,024) and 32,768 times that of a CT of 25 (215=32,768). Clearly, not all positive results are equal, and knowing the CT level of your positive result is of utmost importance.

Thus, the CDC is correct in not wanting false positives to work against the reputation of the vaccines, but why is it OK for false positives to work against the livelihood of Americans? Why is it that only when it comes to the reputation of the vaccines do they suddenly discover the science of false positives? Based on the current CDC standard, the entire contact tracing regime, even to the extent one maniacally believes they can trace a virus that 40% of the country already contracted, should be overhauled….

h/t thc


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