Lockdown easing?

[Nugget]

If I do 2 tests (nose and throat) at the same time, and count them as 2, what vital information do I get, that I wouldn’t if I did only one?
In other words, what conclusion can I draw if the 2 results are different?

Two tests reduces the risk of a false negative:

Professor Keith Neal, an epidemiologist at the University of Nottingham, told MailOnline: 'We know that tests don't always work'.
He added that sometimes people might be tested twice in one go.

'If you do a mouth swab and a nose swab they are separate samples, they would go through the assay separately and would be counted as two tests. If you used the same swab for both it would be one test, but it's not often normal to use the same swab.

For in-hospital cases it might be highly appropriate to make sure you don't miss a diagnosis, particularly if you want to rule out COVID-19. If you do two tests the risk of a false negative is lower.'

[oldoakknives]

Two tests reduces the risk of a false negative:

Professor Keith Neal, an epidemiologist at the University of Nottingham, told MailOnline: 'We know that tests don't always work'.
He added that sometimes people might be tested twice in one go.

'If you do a mouth swab and a nose swab they are separate samples, they would go through the assay separately and would be counted as two tests. If you used the same swab for both it would be one test, but it's not often normal to use the same swab.

For in-hospital cases it might be highly appropriate to make sure you don't miss a diagnosis, particularly if you want to rule out COVID-19. If you do two tests the risk of a false negative is lower.'

Sounds quite sensible. As you say it would involve testing two samples so therefore it is two tests not one.

[Andyg]

If I do 2 tests (nose and throat) at the same time, and count them as 2, what vital information do I get, that I wouldn’t if I did only one?
In other words, what conclusion can I draw if the 2 results are different?

Perhaps it’s one test to determine whether you have/had had Covid and the second test is to determine the viral load.

[Saint-Just]

Sounds quite sensible. As you say it would involve testing two samples so therefore it is two tests not one.

How do you know whether it's a false negative or a false positive? Should we then make 3 tests in one go, as the split would be 2 to 1?

The real question is why do we do these tests?
If we're testing NHS workers, then it's better to test them once every day, or every other day, or every 3 days, or once a week, depending on level of exposure. I am sure there are protocols that have been validated.
If we're testing patients, the double test MAY make sense. Or, it would if we had a place to isolate them before the results came back. In the mean time, where do they go at the moment?
If we're testing the population, and we have an idea of statical percentage of false negative/ false positive, there is no need to double test.

[eoghan101]

Two tests reduces the risk of a false negative:

Professor Keith Neal, an epidemiologist at the University of Nottingham, told MailOnline: 'We know that tests don't always work'.
He added that sometimes people might be tested twice in one go.

'If you do a mouth swab and a nose swab they are separate samples, they would go through the assay separately and would be counted as two tests. If you used the same swab for both it would be one test, but it's not often normal to use the same swab.

For in-hospital cases it might be highly appropriate to make sure you don't miss a diagnosis, particularly if you want to rule out COVID-19. If you do two tests the risk of a false negative is lower.'

The tests that they send to people's houses and the drive through testing use only one swab. Are we to take it that the majority of the tests are people in hospital.

[Nugget]

The tests that they send to people's houses and the drive through testing use only one swab. Are we to take it that the majority of the tests are people in hospital.

That is my understanding

[bloater]

The nose swab requires the swab to be inserted a fair way, the wife did tell me how far, but I've forgotten.
A lot of false negatives are due to the swab not being inserted fully, the ones on the news the wife's seen haven't been inserted enough.

Sent from my VOG-L29 using Tapatalk

[Saint-Just]

If people fear a bad collection then it would make sense to take two swabs, then regroup them in a single test: if there is virus on one, it will register as a positive (within the percentage of confidence of the test). 2 samples, one test. save on tests, increase accuracy. win-win

[davida]

The company I work for started testing employees about a month ago. We have to have two separate test within 48hrs of each other.
With regards to the nasal swab, you have to insert it until you feel resistance which is a lot further back than I would ever have imagined.

[Nugget]

How do you know whether it's a false negative or a false positive? Should we then make 3 tests in one go, as the split would be 2 to 1?

The real question is why do we do these tests?
If we're testing NHS workers, then it's better to test them once every day, or every other day, or every 3 days, or once a week, depending on level of exposure. I am sure there are protocols that have been validated.
If we're testing patients, the double test MAY make sense. Or, it would if we had a place to isolate them before the results came back. In the mean time, where do they go at the moment?
If we're testing the population, and we have an idea of statical percentage of false negative/ false positive, there is no need to double test.

I agree with your point that the number of tests undertaken is not as important as what the purpose of the testing is. For example, how are we progressing against the Five Pillars in our national testing 'strategy'?

Pillar 1: NHS swab testing for those with a medical need and the most critical key workers
Pillar 2: Commercial-swab testing for critical key workers in the NHS, social care and other sectors
Pillar 3: Antibody testing to help determine if people have immunity to coronavirus
Pillar 4: Surveillance testing to learn more about the disease and help develop new tests and treatments
Pillar 5: Diagnostics National Effort to build a mass-testing capacity at a completely new scale

Have we completely cracked Pillars 1 and 2 or are there still key workers not covered (care home workers, for example)? Where are we with Pillar 3?

If you become obsessed with targets and numbers, the risk is that you do testing for the sake of keeping the numbers up and not linked to a clear purpose.

I don't think that it is unreasonable to ask for better information on how the testing being undertaken links to our testing strategy (perhaps this information exists and I have just missed it?).

[ralphy]

And let’s not forget that those 5 Pillars have to be achieved before schools open wider on June 1st.

R

[Andyg]

The devil certainly can be in the detail, so for clarity are you suggesting that the NHS ordering system incorporates the ability to order gloves singly? (How many gloves a surgeon - or any medical practitioner for that matter - chooses to take out of the supplies is irrelevant to the multiples).

R

Clearly you are unfamiliar with examples, however I shall try something perhaps closer to home.

Imagine you fancy some grapes, and you don’t have any. Do you ask buy a “bunch” of grapes, a defined number of grapes, or a specific weight of grapes. If you buy a bunch of grapes, then does this constitute a single item purchase or multiple items? If the second, does this constitute a single item purchase or multiple (especially if consumed in a single sitting (greedy boy) or finally if you buy a weight of grapes, then again does this constitute a single item purchase or multiple?

So if a bunch of grapes can be counted as a single item or many items, then why can’t say a quality of face masks, visor shields, aprons or gloves. Does a single box of say 1000 gloves, count as one item (the box), 500 pairs of gloves, or 1000 individual gloves?

As I said the devil is in the detail, which apparently you don’t have.

I could try to draw you a picture if necessary.

[Tooks]

Straw man alert...

WTF has happened to this place over the weekend?

[AlphaOmega]

With regards to the nasal swab, you have to insert it until you feel resistance which is a lot further back than I would ever have imagined.

I don't want to Google this. Having learned as a boy that the Egyptians used to pull the brains of those destined for mummification out through the nose, presumably there isn't much of a barrier.

But assuming there is a functioning brain in situ, the nasal swab hits some kind of cartilage, does it?

Actually, don't answer that. I'd prefer not to know.

[ralphy]

Clearly you are unfamiliar with examples, however I shall try something perhaps closer to home.

Imagine you fancy some grapes, and you don’t have any. Do you ask buy a “bunch” of grapes, a defined number of grapes, or a specific weight of grapes. If you buy a bunch of grapes, then does this constitute a single item purchase or multiple items? If the second, does this constitute a single item purchase or multiple (especially if consumed in a single sitting (greedy boy) or finally if you buy a weight of grapes, then again does this constitute a single item purchase or multiple?

So if a bunch of grapes can be counted as a single item or many items, then why can’t say a quality of face masks, visor shields, aprons or gloves. Does a single box of say 1000 gloves, count as one item (the box), 500 pairs of gloves, or 1000 individual gloves?

As I said the devil is in the detail, which apparently you don’t have.

I could try to draw you a picture if necessary.

I do so enjoy your analogies Andy; they have a level of surrealism that no-one else here has ever come close to.

R

[JasonM]

Personally, I would like to see the crayon picture.