Potential false-positive rate among the ‘asymptomatic infected individuals’ in close contacts of COVID-19 patients
Objective: As the prevention and control of COVID-19 continues to advance, the active nucleic acid test screening in the close contacts of the patients has been carrying out in many parts of China. However, the false-positive rate of positive results in the screening has not been reported up to now. But to clearify the false-positive rate during screening is important in COVID-19 control and prevention.
Methods: Point values and reasonable ranges of the indicators which impact the false-positive rate of positive results were estimated based on the information available to us at present. The false-positive rate of positive results in the active screening was deduced, and univariate and multivariate-probabilistic sensitivity analyses were performed to understand the robustness of the findings.
Results: When the infection rate of the close contacts and the sensitivity and specificity of reported results were taken as the point estimates, the positive predictive value of the active screening was only 19.67%, in contrast, the false-positive rate of positive results was 80.33%. The multivariate-probabilistic sensitivity analysis results supported the base-case findings, with a 75% probability for the false-positive rate of positive results over 47%.
Conclusions: In the close contacts of COVID-19 patients, nearly half or even more of the ‘asymptomatic infected individuals’ reported in the active nucleic acid test screening might be false positives.
Hopefully it is clear from this study that the prevalence of cases is far lower than is being reported if these tests are being used as predictors of infection.
This testing is as bad as Lyme/MSIDS testing and shouldn’t be taken seriously by anyone.
**UPDATE, March 25, 2020**
Meanwhile, the CDC has developed a new PCR test which is also riddled with problems, intended for labs certified under the Clinical Laboratory Improvement Amendments (CLIA) to perform high complexity tests. (But other CLIA-certified labs doing testing for Lyme/MSIDS are called “home-brewed” by the CDC).
They are also working on a new test which will detect antibodies https://www.cdc.gov/coronavirus/2019-ncov/about/testing.html
The Lyme community is well aware of the short comings of antibody testing as this sort of testing has kept thousands from being diagnosed with tick-borne illness.
Regarding the problems with PCR testing, author David Crowe explains:
To use PCR as a test, you assume that you are starting with an unknown number of strands and end up with an exponential multiple after n cycles. From the quantity of materials at termination the starting quantity can be estimated. A major problem with this is that because PCR is an exponential (doubling) process, errors also grow exponentially.
The second problem is that the Coronavirus is believed to be composed of RNA, but this can be solved by converting all RNA into DNA with the Reverse Transcriptase enzyme at the start of the process.
The technology, after these two adaptations, is known as RT-PCR (Reverse Transcriptase PCR).
Now you have the information necessary to understand the numbers from 20-40 on the vertical axis of the graphs above. These are the number of cycles. It implies that it always took at least 20 PCR cycles before any RNA could be detected, and they stopped after a maximum of 37 cycles. The blue line is at cycle 38, and the black dots do not mean RNA was detected after 38 cycles (as clarified in the paper), but that it wasn’t detected by 37 cycles, and so the process terminated. This “Serial Cycle Threshold (Ct)” was the arbitrary definition of a negative result by the authors of reference .
We can see that it was arbitrary, because in another paper, reference , the authors had two end points: 37 and 40. Anything less than 37 was considered positive and anything 40 or greater was defined as negative. The in-between values were re-tested and re-interpreted. Note that this paper would treat 37 as indeterminate but the Singapore paper would treat it as positive. https://madisonarealymesupportgroup.com/2020/03/16/does-the-coronavirus-exist/
His paper goes on to show many people testing positive, then negative, then positive again. Results were all over the place. Regarding antibody cut off points, the Lyme/MSIDS community again, is all too aware of how this has kept people from being diagnosed, only instead of false positives as in COVID-19 testing, it’s false negatives that are killing Lyme patients. False positives only serve those who want to show high numbers of infected people.
Recently I posted a video of Dr. Wolfgang Wodarg, pulmonologist, epidemiologist, and past chairman of the Parliamentary Assembly of the Council of Europe Health Committee. He states the following on his website, regarding testing:
Without PCR-Tests there would be no reason for special alarms.
We are currently not measuring the incidence of coronavirus diseases, but the activity of the specialists searching for them.https://www.wodarg.com
BTW, Wodarg is the one who pointed out the Swine flu hoax and states this:
We have experienced similar alarmist actions by virologists in the last two decades. WHO’s “swine flu pandemic” was in fact one of the mildest flu waves in history and it is not only migratory birds that are still waiting for “birds flu”. Many institutions that are now again alerting us to the need for caution have let us down and failed us on several occasions. Far too often, they are institutionally corrupted by secondary interests from business and/or politics. https://www.wodarg.com
Lastly, he states
It is a well-known fact that in every “flu wave” 7-15% of acute respiratory illnesses (ARI) are coming along with coronaviruses, the case numbers that are now continuously added up are still completely within the normal range. https://www.wodarg.com
NAT technique is highly sensitive and specific for viral nucleic acids. It is based on amplification of targeted regions of viral ribonucleic acid or deoxyribonucleic acid (DNA) and detects them earlier than the other screening methods thus, narrowing the window period of HIV, HBV and hepatitis C virus (HCV) infections.
- highly technically demanding
- high cost
- dedicated infrastructure facility
- technical expertise
- And lastly, at least regarding COVID-19 – the high false positive rate
And then, the latest attention grab is COVID-19 testing is that is supposed to give results within 45 minutes, such as this one from Cepheid: https://www.cepheid.com/coronavirus. The problem is, if the test is inaccurate to begin with, getting the results quicker isn’t any more helpful. We are told here by a Yale MD that COVID-19 is mutating: https://madisonarealymesupportgroup.com/2020/03/21/its-not-the-exact-same-virus-everywhere-in-the-world/
Current tests only detects SARS-CoV-2.
Hopefully this demonstrates that the numbers floating out there are all based upon faulty testing – just like Lyme/MSIDS. Again, I’m not saying people don’t die of viruses – they do – and they always have and most probably always will. But, this thing is being blown up to monster proportions when frankly, they haven’t a clue on prevalence.