May 7, 2021

Positive Covid test? ask for the Cycle Threshold (CT) value

PCR test and Cycle Threshold rusults
Cycle Threshold

The lockdowns are based on surging “cases” which are based on positive PCR test results. However, what exactly is a positive PCR test result? What does it mean?

  • Am i infectious?
  • Who is infectious?
  • Who will develop Covid, the disease?
  • Where is the virus actively spreading? (and we’d like it to be error free)
what is CT value in an RT PCR Test

More covid-19 news: Ivermectin is effectively a ”miracle drug” against COVID-19

After you test positive, ask this question: at what cycle threshold (CT) did my test return a positive result?

Keeping things straight

  • ”Covid-19” is the disease while SARS- CoV-2 is the virus
  • ”Case” an infected requiring medical attention
  • ”Positive” meaningless without knowing PCR Cycle Threshold. Could be an active infection or an old fragment.
  • ”False Positive” A big problem especially for low prevalence diseases.
  • ”Negative” Possibly meaningful. Doesn’t indicate if person had ever been infected or not.
  • ”False Negative” A problem, but not as big as false positives (specificity is higher)
  • ”Infective or infectious” This is what we actually (should) care about most.

PCR reaction Cycles

PCR reaction Cycles
PCR reaction Cycles

Cycle Thresholds Too Damn High

Officials at the Wadsworth Center, New York’s state lab, have access to C.T. values from tests they have processed, and analyzed their numbers at The Times’s request. In July, the lab identified 872 positive tests, based on a threshold of 40 cycles.

With a cutoff of 35, about 43 percent of those tests would no longer qualify as positive. About 63 percent would no longer be judged positive if the cycles were limited to 30.

PCR test labor
Cycle threshold

In Massachusetts, from 85 to 90 percent of people who tested positive in July with a cycle threshold of 40 would have been deemed negative if the threshold were 30 cycles, Dr. Mina said. “I would say that none of those people should be contact-traced, not one,” he said.

Other experts informed of these numbers were stunned.

“I’m really shocked that it could be that high — the proportion of people with high C.T. value results,” said Dr. Ashish Jha, director of the Harvard Global Health Institute. “Boy, does it really change the way we need to be thinking about testing.”

more info: Cycle Thresholds too damn High

A Cycle Threshold over 35 is Non-infectious

Strong Inverse Correlation Between SARS-CoV-2 Infectivity and Cycle Threshold Value

Correlation between successful isolation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in cell culture and cycle threshold (Ct) value of quantitative reverse transcription polymerase chain reaction (RT-PCR) targeting E gene suggests that patients with coronavirus disease 2019 (COVID-19) with Ct above 33 to 34 are not contagious and can be discharged from hospital care or strict confinement, according to a brief report published in the European Journal of Clinical Microbiology & Infectious Diseases.

More info: CT over 35 is non-infectious

Review report Corman-Drosten et al. Eurosurveillance 2020

November 27, 2020

This extensive review report has been officially submitted to Eurosurveillance editorial board on 27th November 2020 via their submission-portal, enclosed to this review report is a retraction request letter, signed by all the main & co-authors. First and last listed names are the first and second main authors. All names in between are co-authors.

External peer review of the RTPCR test to detect SARS-CoV-2 reveals 10 major scientific flaws at the molecular and methodological level: consequences for false positive results.

3. The number of amplification cycles

It should be noted that there is no mention anywhere in the Corman-Drosten paper of a test being positive or negative, or indeed what defines a positive or negative result.

These types of virological diagnostic tests must be based on a SOP, including a validated and fixed number of PCR cycles (Ct value) after which a sample is deemed positive or negative. The maximum reasonably reliable Ct value is 30 cycles. Above a Ct of 35 cycles, rapidly increasing numbers of false positives must be expected .

Further, scientific studies show that only non-infectious (dead) viruses are detected with Ct values of 35 [22].

Between 30 and 35 there is a grey area, where a positive test cannot be established with certainty. This area should be excluded. Of course, one could perform 45 PCR cycles, as recommended in the Corman-Drosten WHO-protocol (Figure 4), but then you also have to define a reasonable Ct-value (which should not exceed 30).

But an analytical result with a Ct value of 45 is scientifically and diagnostically absolutely meaningless (a reasonable Ct-value should not exceed 30). All this should be communicated very clearly. It is a significant mistake that the Corman-Drosten paper does not mention the maximum Ct value at which a sample can be unambiguously considered as a positive or a negative test-result. This important cycle threshold limit is also not specified in any follow-up submissions to date.

More info: Corman Drosten retraction request

WHO PCR test instructions? YES! they use 45 Cycles? Thats absolutely meaningless

More info: WHO PCR 47 (!) Cycles

Test have shown that live Sars2 cannot be grown from samples where the CT was 35 or greater. Thus any result smaller 35 would absolutely have to be confirmed with clinical symptoms to be declared a ”positive.”

Any positive PCR result with CT (Cycle Threshold) of 30 or lower indicates an active infection. Treat accordingly!

Any CT between 30 and 35 is suspect. May indicate active infection,or may be inactive, or may be inactive or a false positive. Take prophylactic measures, but don,t worry too much.

Any CT between 35 and 40 is increasingly noisy (useless) Might be an asymptomatic. Might have gotten over it. Might be at the early stages. But unless clinical symptoms, nothing to worry about.

Any CT ”positive” result over 40 is complete garbage! or more gently, ”scientifically and diagnostically meaningless.”

The WHO,s test standards with a CT of 45 is beyond garbage!

Why aren’t the Cycle threshold results disclosed as a routine part of information flow and decision making?

More link info:

Kansas CT cutoff of 42

UK PCR positive standards

CT over 35 is non-infectious

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