Explain testing

[Marauder2003]

Given that testing results seems to take 15 minutes to 3 days why is testing so important? All the results show is that you were or were not infected at the moment of testing. If it shows you were infected you have had 15 minutes to 3 days to infect others. If you were not infected you have had 15 minutes to 3 days to get infected.

[capo]

Explain testing

Two reasons: backtracking to quarantine people they'd had recent close contact with and to isolate people (including initial test case) who have the virus in their system. The pathogen can't spread effectively if anyone who has had exposure is separated from the general public. This virus has a long incubation period, that allows for more effective tracking and isolation.

Rapid testibg is key to how we'll ultimately open things back up and prevent new outbreaks from entering exponential growth. Individual cases can remain isolated to individuals or immediate friends and family rather than progressing to general community spread every time.

[NATO762]

Pipe down peasant. Are you questioning our public health overlords?

This is why the antibody tests are much more valuable for the population at large. It's also why the "do I have CV?" tests are generally only being used at point of care, and to folks visiting the Whitehouse.

[Marauder2003]

A person getting a clean test can get infected unknowingly and not worry because they had a clean test.

Until vaccines are available and taken the clean test person is dangerous.

[NATO762]

Bingo. And that's why there is no mass testing being done. It's only used to confirm a suspected case, and for contact tracing as capo says. It's only useful with a positive result. As you say a negative test is only as good as fresh fish.

Which is why the serology (antibody) test is the one I'm betting on.

[Doheny]

A person getting a clean test can get infected unknowingly and not worry because they had a clean test.



Until vaccines are available and taken the clean test person is dangerous.

This.


Sent from free America

[PopsA408]

Testing serves two purposes, epidemiological, and diagnostic. With the 2009 H1N1 pandemic the introduction of real time rt-PCR tests to both the state Public Health labs and most major hospitals created an extended network across all 50 states. This network was capable of performing both surveillance and diagnostics for specific influenza targets, differentiating between seasonal influenza and pandemic influenza. This was critical in both surveillance and treatment.

Because the same instruments and chemistry, along with designed tests were being run in both state labs and hospitals the FDA stepped in and declared all of it to fall under the realm of diagnostics. While this slowed the process of getting tests to operational status, it did ultimately created a much larger network for both epidemiology and diagnostics. As public health surveillance could trust the results coming from hospitals and doctors could trust results coming from public health labs.

Unfortunately funding for much of this was lost after 2009 and the public health labs lost a lot of capacity. And the spin up was very slow.

[capo]

A person getting a clean test can get infected unknowingly and not worry because they had a clean test.

Until vaccines are available and taken the clean test person is dangerous.

A negative test is of highest value for symptomatic people, it helps to exclude them from the population carrying this novel virus. Clinical diagnosis can then proceed to detect what other virus they may have and to treat accordingly but they aren't a danger to others for passing on this pandemic.

If any individual suspected of being exposed tests negative while within the incubation window they will have to continue to test negative until they have passed that period. A positive test triggers isolation and treatment but a negative test doesn't stop their quarantine.

If anyone can't understand what their physician tells them about the meaning of a negative test you certainly can't blame the testing for that. Ignorance doesn't devalue the results.

[Sousuke]

A person getting a clean test can get infected unknowingly and not worry because they had a clean test.

Until vaccines are available and taken the clean test person is dangerous.

In the post closure future, if you are contacted by health authorities asking to get tested (because you will have been in contact with someone who has the virus) you will probably face two tests. An initial one that if negative, would still require you to isolate and then be tested again.

[PopsA408]

A negative test is of highest value for symptomatic people, it helps to exclude them from the population carrying this novel virus. Clinical diagnosis can then proceed to detect what other virus they may have and to treat accordingly but they aren't a danger to others for passing on this pandemic.

If any individual suspected of being exposed tests negative while within the incubation window they will have to continue to test negative until they have passed that period. A positive test triggers isolation and treatment but a negative test doesn't stop their quarantine.

If anyone can't understand what their physician tells them about the meaning of a negative test you certainly can't blame the testing for that. Ignorance doesn't devalue the results.

[capo]

One note: the CDC design PCR test actually does test for and distinguish between SARS-CoV2 and other coronavirus strains. IIRC assays 1 & 2 test for sequences unique to SARS-CoV2, assay 3 tests for sequences shared between all circulating coronavirus strains while assay 4 is the control test.

I agree antibody testing is what we need more of, just not sure how specific those tests can be for this strain vs other coronavirus antibodies. If they are really sensitive tests I don't think they'll be very good at eliminating positive results for other strains.

[numpty]

One note: the CDC design PCR test actually does test for and distinguish between SARS-CoV2 and other coronavirus strains. IIRC assays 1 & 2 test for sequences unique to SARS-CoV2, assay 3 tests for sequences shared between all circulating coronavirus strains while assay 4 is the control test.

I agree antibody testing is what we need more of, just not sure how specific those tests can be for this strain vs other coronavirus antibodies. If they are really sensitive tests I don't think they'll be very good at eliminating positive results for other strains.

My whole family got really sick end of February. I was sicker than I can remember being and my wife who will get sick for a day or two was down for over a week. Three kids went down for about 10 days too. Whatever it was went through our house like a fricken' tornado. A few of our friends and their families had similar experiences.

I just want to know if we've already had it.

[PopsA408]

One note: the CDC design PCR test actually does test for and distinguish between SARS-CoV2 and other coronavirus strains. IIRC assays 1 & 2 test for sequences unique to SARS-CoV2, assay 3 tests for sequences shared between all circulating coronavirus strains while assay 4 is the control test.

I agree antibody testing is what we need more of, just not sure how specific those tests can be for this strain vs other coronavirus antibodies. If they are really sensitive tests I don't think they'll be very good at eliminating positive results for other strains.

That is the limit of antibody testing, specificity. Well, sensitivity too when compared to PCR which can detect a single copy of a target in a sample.

I have seen some antibody substrates which are far better than others, magnetic beads for example. And in a workflow certainly can serve a valuable purpose for screening at a high level, is it a corona virus for example? Then run PCR for the positives to subtype them for which strain.

[DoNotReply]

I have my Antibody test scheduled for this Tuesday. My wife, kids and I all had fevers and flu like symptoms a month or so ago. The Telehealth nurse I spoke too said it really doesn't prove anything if it does come back positive since there is more than one strain and you could still be infected again. Either way, still curious. I've spent $50 on worse.