COVID-19 PCR Test protocol, Sensitivity, Specificity and therefore Operational False Positive Rate, and how the official figures are corrected for this

Jonathan Dench made this Freedom of Information request to Office for National Statistics

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Dear Office for National Statistics,

I have some strong scientific concern about COVID-19 testing and the handling of data by the UK Government.

Firstly no-specificity or sensitivity is provided which is completely unacceptable. It appears data is not being corrected for the Operational false positive rate of such tests. Current estimates of specificity from the literature are 95-99% ,this does not sound alarming at first, but once you account for test frequency and prevalence this is quite alarming, as it would provide an operational false positive rate of 90%. This can be confirmed from "with COVID death' data ie died within 28 days of positive PCR. If you compare current excess death with the average of the past 5 years with the governments estimates of COVID death, you get an Operational false positive rate of 70% for a sample with the highest pre-test probability of having COVID and therefore the lowest OFPR. This means the government statistics are meaningless without correction. This also means no mass indescriminate testing should take place as this would further worsen this problem. You should be doing a full investigation on this matter, as the Government draws us further into a pseudo pandemic.

What I am requesting:

Full PCR test protocol
Test sensitivity
Test specificity
How data is being corrected for Operational false positive rate.

If you cannot provide these then you should not be using PCR as a diagnostic test and a full investigation should be launched immediately.

Yours faithfully,

Dr Jonathan Dench

Yours faithfully,

Jonathan Dench,

Workflow Notification

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1. mailto:[ONS request email]

FOI Team, Office for National Statistics

Our Reference: FOI/2020/1221


Dear Jonathan


Thank you for your email requesting data pertaining to sensitivity,
specificity, and protocol for COVID-19 PCR testing.


I am writing to confirm that the Office for National Statistics has now
completed its search for the information which you requested and the
response can be found here:



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The Freedom of Information Team

Office for National Statistics


For information on Coronavirus, please visit [2]



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Dear FOI Team,

Your estimate, of Specificity is only valid for the testing undertaken during the first lockdown. When standards of testing was much higher and only people likely to have the virus were tested. This estimate is no-longer correct. Please can you also stop the government incorrectly indicating number of positive tests == number of COVID 19 cases. This is emphatically incorrect

Yours sincerely,

Jonathan Dench

FOI Team, Office for National Statistics

Dear Jonathan,


Thank you for your email.


We have consulted our COVID-19 Infection Survey team, who have confirmed
that we would not expect the technical false positivity rate to have
changed since the first lockdown. More recent evidence to support this can
be found in the paper our academic partners published [1]here, which may
be of interest.


With regards to your comments on the way the government are presenting the
number of COVID-19 cases, this feedback would be better directed to Public
Health England (PHE), as they are responsible for the overall number of
positive test figures to which you refer. They can be contacted via email
at [2][email address].   


Kind regards,


The Freedom of Information Team | UK Statistics Authority | Awdurdod
Ystadegau’r Deyrnas Unedig

@UKStatsAuth | [3][email address] |



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