Discussion:
OT: Covid testing ?
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BrritSki
2020-11-16 17:48:41 UTC
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"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said that
lateral flow tests [have] less than five per thousand false positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.

3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.

This is not a conspiracy theory or attempt to claim that COVID does not
exist - we are being very careful, following the rules wearing masks
etc. and will continue to do so.

But what is the explanation for these results ? I know that the LF test
only detects people that are actually infectious whereas the PCR test
detects any level of viral fragment traces*, but this would seem to
indicate that there are very few infectious people in Liverpool which
was one of the hotspots when we locked down again not very long ago.

TIA for clarification. Confused of Bedford

* another report I saw today from a court case in Portugal said “if
someone is tested by PCR as positive when a threshold of 35 cycles or
higher is used (as is the rule in most laboratories in Europe and the
US), the probability that said person is infected is <3%, and the
probability that said result is a false positive is 97%.”
I read some time ago some expert in PCR testing that you should not do
more than 30-35 cycles and that she would personally stick to 30
iterations, and that in the UK we are doing 40 !!!
Sid Nuncius
2020-11-16 19:08:06 UTC
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Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said that
lateral flow tests [have] less than five per thousand false positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
ICBAM, but I take "five per thousand false positives" to mean five false
positives per one thousand *positive* tests - i.e. an accuracy of 99.5%,
so that 1 or 2 of the 336 positives detected would be expected to be
false positives.

Whether or not one believes the claim is another matter, of course.
Post by BrritSki
But what is the explanation for these results ?  I know that the LF test
only detects people that are actually infectious whereas the PCR test
detects any level of viral fragment traces*, but this would seem to
indicate that there are very few infectious people in Liverpool which
was one of the hotspots when we locked down again not very long ago.
It equates to around 370 per 100,000, which is a high rate compared to
the current national average.

I repeat, I could be wrong about all of the above - it's my
interpretation rather than from any authoritative source.
--
Sid
(Make sure Matron is away when you reply)
BrritSki
2020-11-16 19:19:46 UTC
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Post by Sid Nuncius
Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said
that lateral flow tests [have] less than five per thousand false
positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
ICBAM, but I take "five per thousand false positives" to mean five false
positives per one thousand *positive* tests - i.e. an accuracy of 99.5%,
so that 1 or 2 of the 336 positives detected would be expected to be
false positives.
Not my understanding, but maybe you are right. I thought it was 99.5%
accurate overall. Need to look into this more.... Thanks.
Post by Sid Nuncius
Whether or not one believes the claim is another matter, of course.
Post by BrritSki
But what is the explanation for these results ?  I know that the LF
test only detects people that are actually infectious whereas the PCR
test detects any level of viral fragment traces*, but this would seem
to indicate that there are very few infectious people in Liverpool
which was one of the hotspots when we locked down again not very long
ago.
It equates to around 370 per 100,000, which is a high rate compared to
the current national average.
True, but if they're ALL detecting more than are really dangerous
because of the 40 iterations... and excess deaths all over Europe are
lower than normal for the time of year despite all these extra "cases".

I saw somewhere recently that the Gov't could lift the siege any time
they wanted simply by reducing the iteration rate. I suspect that is
what has already happened in some of the countries that have "beaten"
the virus such as China.

This is all sounding a bit tinfoil hat country, but there seems to be a
lot of unnecessary hysteria about imo.
Mike McMillan
2020-11-17 09:12:16 UTC
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Permalink
Post by BrritSki
Post by Sid Nuncius
Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said
that lateral flow tests [have] less than five per thousand false
positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
ICBAM, but I take "five per thousand false positives" to mean five false
positives per one thousand *positive* tests - i.e. an accuracy of 99.5%,
so that 1 or 2 of the 336 positives detected would be expected to be
false positives.
Not my understanding, but maybe you are right. I thought it was 99.5%
accurate overall. Need to look into this more.... Thanks.
Post by Sid Nuncius
Whether or not one believes the claim is another matter, of course.
Post by BrritSki
But what is the explanation for these results ?  I know that the LF
test only detects people that are actually infectious whereas the PCR
test detects any level of viral fragment traces*, but this would seem
to indicate that there are very few infectious people in Liverpool
which was one of the hotspots when we locked down again not very long
ago.
It equates to around 370 per 100,000, which is a high rate compared to
the current national average.
True, but if they're ALL detecting more than are really dangerous
because of the 40 iterations... and excess deaths all over Europe are
lower than normal for the time of year despite all these extra "cases".
I saw somewhere recently that the Gov't could lift the siege any time
they wanted simply by reducing the iteration rate. I suspect that is
what has already happened in some of the countries that have "beaten"
the virus such as China.
This is all sounding a bit tinfoil hat country, but there seems to be a
lot of unnecessary hysteria about imo.
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!

How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
--
Toodle Pip (My other iPad is an old Pro)
DavidK
2020-11-17 10:05:39 UTC
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Post by Mike McMillan
Post by BrritSki
Post by Sid Nuncius
Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said
that lateral flow tests [have] less than five per thousand false
positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
ICBAM, but I take "five per thousand false positives" to mean five false
positives per one thousand *positive* tests - i.e. an accuracy of 99.5%,
so that 1 or 2 of the 336 positives detected would be expected to be
false positives.
Not my understanding, but maybe you are right. I thought it was 99.5%
accurate overall. Need to look into this more.... Thanks.
Post by Sid Nuncius
Whether or not one believes the claim is another matter, of course.
Post by BrritSki
But what is the explanation for these results ?  I know that the LF
test only detects people that are actually infectious whereas the PCR
test detects any level of viral fragment traces*, but this would seem
to indicate that there are very few infectious people in Liverpool
which was one of the hotspots when we locked down again not very long
ago.
It equates to around 370 per 100,000, which is a high rate compared to
the current national average.
True, but if they're ALL detecting more than are really dangerous
because of the 40 iterations... and excess deaths all over Europe are
lower than normal for the time of year despite all these extra "cases".
I saw somewhere recently that the Gov't could lift the siege any time
they wanted simply by reducing the iteration rate. I suspect that is
what has already happened in some of the countries that have "beaten"
the virus such as China.
This is all sounding a bit tinfoil hat country, but there seems to be a
lot of unnecessary hysteria about imo.
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!
How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
There is a good "More or Less" on false positives,
https://www.bbc.co.uk/sounds/play/m000mr42 @ 8:47, but it didn't stay
long in my mind.
Vicky Ayech
2020-11-17 12:05:17 UTC
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Permalink
Post by DavidK
Post by Mike McMillan
Post by BrritSki
Post by Sid Nuncius
Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said
that lateral flow tests [have] less than five per thousand false
positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
ICBAM, but I take "five per thousand false positives" to mean five false
positives per one thousand *positive* tests - i.e. an accuracy of 99.5%,
so that 1 or 2 of the 336 positives detected would be expected to be
false positives.
Not my understanding, but maybe you are right. I thought it was 99.5%
accurate overall. Need to look into this more.... Thanks.
Post by Sid Nuncius
Whether or not one believes the claim is another matter, of course.
Post by BrritSki
But what is the explanation for these results ?  I know that the LF
test only detects people that are actually infectious whereas the PCR
test detects any level of viral fragment traces*, but this would seem
to indicate that there are very few infectious people in Liverpool
which was one of the hotspots when we locked down again not very long
ago.
It equates to around 370 per 100,000, which is a high rate compared to
the current national average.
True, but if they're ALL detecting more than are really dangerous
because of the 40 iterations... and excess deaths all over Europe are
lower than normal for the time of year despite all these extra "cases".
I saw somewhere recently that the Gov't could lift the siege any time
they wanted simply by reducing the iteration rate. I suspect that is
what has already happened in some of the countries that have "beaten"
the virus such as China.
This is all sounding a bit tinfoil hat country, but there seems to be a
lot of unnecessary hysteria about imo.
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!
How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
There is a good "More or Less" on false positives,
long in my mind.
https://twitter.com/vegsource/status/1322285840291147776
Vicky Ayech
2020-11-17 12:06:52 UTC
Reply
Permalink
Post by DavidK
Post by Mike McMillan
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!
How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
There is a good "More or Less" on false positives,
long in my mind.

Steve Hague
2020-11-17 12:33:34 UTC
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Permalink
Post by Vicky Ayech
Post by DavidK
Post by Mike McMillan
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!
How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
There is a good "More or Less" on false positives,
long in my mind.
http://youtu.be/a_Vy6fgaBPE
Due to being a regular church attender, I probably come into close
contact with more people than most, and we are a very huggy church.
There's usually about 250 of us close together on a Sunday morning. One
of our people became ill last December before covid was a known thing,
but her blood samples were kept, and later tested positive. Another
woman became ill in February with covid type symptoms, and was in
hospital for a couple of days. After that, zilch. Nothing. It's hardly
the Black Death, is it.
Chris McMillan
2020-11-19 21:53:17 UTC
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Permalink
Post by Steve Hague
Post by Vicky Ayech
Post by DavidK
Post by Mike McMillan
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!
How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
There is a good "More or Less" on false positives,
long in my mind.
http://youtu.be/a_Vy6fgaBPE
Due to being a regular church attender, I probably come into close
contact with more people than most, and we are a very huggy church.
There's usually about 250 of us close together on a Sunday morning. One
of our people became ill last December before covid was a known thing,
but her blood samples were kept, and later tested positive. Another
woman became ill in February with covid type symptoms, and was in
hospital for a couple of days. After that, zilch. Nothing. It's hardly
the Black Death, is it.
Sadly, not the case here, Steve, with figures climbing rapidly every day.
A local secondary school has 20 year 9s isolated this week but the school
has had cases every week since Sept. One of my friends is highly
vulnerable, her daughter is a Yr 9 and they had seriously considered
sending daughter to live elsewhere but she couldn’t do it. The other day,
with Covid like symptoms, my friend did a home test. Inconclusive. She
reluctantly went to hospital for several hours yesterday but was let out
because with her complicated medical condition her house is better managed,
but who knows what I might hear.

Another friend, just 80, was hospitalised for three weeks having contracted
it by someone passing by in a local eaterie. Another one very vulnerable.

Back when you’re talking about, yes, our church too caught several people,
of ages thirties to over 70, plus a secondary school son of one family.
All the adults suffered badly and were unwell for weeks not days. Us in
built on Britain are at far worse risk than the thinly populated areas.

There’s interactive maps around where if you know your county minutely, you
can look up ward by ward and see how many each has, including deaths,
living on several borders as we do of a ward, and two adjoining towns, it’s
been interesting to see how just a few hundred yards make a difference
because of housing types, demographics and footfall.

Sincerely Chris

BrritSki
2020-11-17 13:59:29 UTC
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Permalink
Post by DavidK
Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said
that lateral flow tests [have] less than five per thousand false
positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
There is a good "More or Less" on false positives,
long in my mind.
That is very interesting. The relevant part is the 6 minutes from about
9.20.

That supports my contention that the false +ve rate is of the number of
tests not of the +ves (as Hancock got wrong too), but then goes on to
point out that it is very important to consider the population that is
infected.

If 1,000 people are tested and they are all symptomatic you would expect
quite a lot of them to be true +ves, so the 5 false +ves (with a .5%
rate is not very concerning.

If however you're testing a random sample of the population where very
few are infected at any given time, the 5 false +ves is much more
relevant. This is what was happening in the Liverpool testing, which was
of the whole population.

The Prof in the podcast suggests that the rate of false +ves is much
less than the .8% they were discussing, but I'm guessing that if it was
MUCH lower than .5%, the good Dr Hopkins would have used the lower figure.

I therefore repeat my assertion that very few of the 336 +ves found in
Liverpool were true positives.

The BMJ have serious concerns too
<https://www.bmj.com/content/371/bmj.m4436>
Vicky Ayech
2020-11-17 11:06:28 UTC
Reply
Permalink
On Tue, 17 Nov 2020 09:12:16 GMT, Mike McMillan
Post by Mike McMillan
Post by BrritSki
Post by Sid Nuncius
Post by BrritSki
"Dr Susan Hopkins, medical adviser to NHS Test and Trace, has said
that lateral flow tests [have] less than five per thousand false
positives...!
I just heard her say this and the above is a partial quote from the
Telegraph.
3 days ago the BBC reported that there had been 90,000 tests in
Liverpool and found 336 positives. Something does not add up - there
should be 450 false positives expected.
ICBAM, but I take "five per thousand false positives" to mean five false
positives per one thousand *positive* tests - i.e. an accuracy of 99.5%,
so that 1 or 2 of the 336 positives detected would be expected to be
false positives.
Not my understanding, but maybe you are right. I thought it was 99.5%
accurate overall. Need to look into this more.... Thanks.
Post by Sid Nuncius
Whether or not one believes the claim is another matter, of course.
Post by BrritSki
But what is the explanation for these results ?  I know that the LF
test only detects people that are actually infectious whereas the PCR
test detects any level of viral fragment traces*, but this would seem
to indicate that there are very few infectious people in Liverpool
which was one of the hotspots when we locked down again not very long
ago.
It equates to around 370 per 100,000, which is a high rate compared to
the current national average.
True, but if they're ALL detecting more than are really dangerous
because of the 40 iterations... and excess deaths all over Europe are
lower than normal for the time of year despite all these extra "cases".
I saw somewhere recently that the Gov't could lift the siege any time
they wanted simply by reducing the iteration rate. I suspect that is
what has already happened in some of the countries that have "beaten"
the virus such as China.
This is all sounding a bit tinfoil hat country, but there seems to be a
lot of unnecessary hysteria about imo.
Having followed the above postings from people (UMRATS) for whom I have a
high regard for their integrity intelligence, thoroughness in their
consideration and research of the ‘facts’ as offered to the general public
and generally their level headedness, I conclude that it is very easy to
hoodwink the ‘general public’ into accepting (I was going to say
‘believing’ but, perhaps even the general public are not *that* gullible!)
just what the government and other authorities ‘want’ us to accept!
How on earth are members of the public at large supposed to follow the
arguments and glean any real intelligence from what they are told? I am an
intelligent person but have not exerted a tenth of the energy some other
UMRATS have in investigating this whole sorry affair I’m afraid - perhaps I
should apply myself more but, then I think ....*What the Hell???* Much
effort has been applied by the learned medics, statisticians and
governmental bodies - yet - differences in opinion are still so wide! Ho
-Hum and Harrumph!
There are a few books that remind me of how it is now. The Caves of
Steel, Asimov, The Killer with the Knife , Nicholas Blake, are two.
How to get most of the population to accept things and censor anyone
who does not.
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