Tokyo reports 102 new coronavirus cases

This is a link the the USFDA emergency approval findings for one RTーPCR test, including data on sensitivity and specificity. It finds that the test is has a low rate of false positives and is specific to nCov-SARS-2 when subjected to analysis:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.fda.gov/media/136151/download&ved=2ahUKEwjVvv_ll9LsAhXIAYgKHattAJsQFjAAegQIAhAB&usg=AOvVaw01KKYbfY1uDX6dREqk8iCf

In real world application, the false positive rate has been estimated at between 0.8 and 4% in the UK amongst low incidence groups:(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7457918/)

Looking at these studies as a layperson, my interpretation is that false positives are not a significant issue for wide testing regimes where mitigation is put in place. For example, high standards for sample collection and handling, retesting following inconclusive or positive results to confirm diagnosis, and prioritising pretest screening for those at high risk of exposure or health complications (i.e. service staff, medical staff, and individuals with comorbidities).

Its fine to think that Japans method is working fine, but buying into some conspiracy that the situation on other countries is somehow false due to test failure is to diminish the global nature of the pandemic.

The accuracy of the test is 99%... Not 9% or 0.1% or whatever number that people that haven't studied Probability and statistics are trying to make you believe.

Some Japanese media confused independent and conditional probabilities... and now all Japan believes that the PCR test are all wrong.

Would be nice if Japan followed the international PRC testing flows, so we could compare with other countries.

The "This Is Japan!" system is making me sick already.

Massively testing the population so you have an accurate figure of the number of sick people

We are 10 months into the pandemic, if testing wasn't increased in the early stage of the pandemic

when little was known of the virus, it won't now that it is well known that the vast majority especially

the young and healthy don't need hospitalization and a lot of positive cases are asymptomatic.

Nobody talks any longer on the mainstream media about testing and the few experts that talked about the merits of increasing testing like professor Harue Okada of Hakuoh university don't appear any longer on T.V.

Mitigating the virus has never been the intent so it is left to each and everyone to take the necessary precaution.

Would be nice if Japan followed the international PRC testing flows, so we could compare with other countries.

What is/are the international PRC testing flows?

brilliant figure - possibly a few times higher than that, but still very low.

This is the way to do it. Test widely then isolate positive cases so they cannot further spread the disease.

exactly

BBC News headline today:

"One virus case sparks mass testing in Xinjiang...

Kashgar city officials say around 4.7m people will be tested over a few days."

This is the way to do it. Test widely then isolate positive cases so they cannot further spread the disease.

In real world application, the false positive rate has been estimated at between 0.8 and 4% in the UK amongst low incidence groups

I've just heard (has yet to confirm) the info that UK as well as European countries adopt a higher Ct value for own PCR, set at 42-45... if true, I think it unusual, hyper-sensitive and risky of producing many false positive results. Even Taiwan with one of the most restrictive measures arranges Ct at around 35.

In UK, for example, even people in a late recovering phase with zero infectious risk might still get positive result (and forced quarantine to no avail).

But why ? What is the nice bit ? What are we comparing ? And what if this is done ; what then ; do it again next week ?

Your answer is posted already: BartoToday  05:51 pm JST

@monty

whining day by day about lack of tests.

We had to complain for 9 months to finally let the residents get back to their Japanese homes as the Japanese natives were doing.

I wonder how much longer do we have to complain to get massive tests done in general population.

@dr.lucifer

it is left to each and everyone to take the necessary precaution.

I agree with you. After 10 months people should finally understand how to do their own personal best prevention, and they should stop whining day by day about lack of tests.

@garth

Kashgar city officials say around 4.7m people will be tested over a few days."

Dont believe everything what China is telling.

They only know how to tell lies !

I haven't read anything definitive on it, always just vague references to this massive testing, with no info at all on how to implement. Could you provide a good source please.

Im interested specifically how to address false positives where prevalence of covid-19 is thought to be low

Massively testing the population so you have an accurate figure of the number of sick people, with or without symptoms, then you can quarantine them to preserve elderly and treat them so they don't spread the virus more.

But why ? What is the nice bit ? What are we comparing ? And what if this is done ; what then ; do it again next week ?

The "This Is Japan!" system is making me sick already.

Quite honestly I don't see other, more constructive way to reply without triggering a long pointless conversation comparing economies priorities national security and whatnot

speechless here

In real world application, the false positive rate has been estimated at between 0.8 and 4% in the UK amongst low incidence groups

Hmmm, so if we have similar rates here, then out of the 2987 tests performed, we would get 24-119 false positive results.

So I wonder what fraction of the reported 102 cases are real cases.

What is/are the international PRC testing flows?

Its inflating numbers with false positives to keep the sheep in line through fear. How are politicians supposed to enjoy their god-given right to absolute authority if the numbers don't cooperate?

Places like Victoria and Wales get it right