COVID-19 AB Testing - please read !!!!

[ventana]

a good summary - - -  https://www.npr.org/sections/health-shots/2020/05/01/847368012/how-reliable-are-covid-19-tests-depends-which-one-you-mean

 

 

Lets stop the madness and call a donkey a donkey and not a though bred horse.......

 

Antibody test

What it does: Antibody tests identify people who have previously been infected with the coronavirus. They do not show whether a person is currently infected. This is primarily a good way to track the spread of the coronavirus through a population.

SHOTS - HEALTH NEWS

A Next-Generation Coronavirus Test Raises Hopes And Concerns

How it works: This is a blood test. It looks for antibodies to the coronavirus. Your body produces antibodies in response to an infectious agent such as a virus. These antibodies generally arise after four days to more than a week after infection, so they are not used to diagnose current disease.

How accurate is it: There are more than 120 antibody tests on the market. The Food and Drug Administration has allowed them to be marketed without FDA authorization, and quality is a great concern. A few tests have voluntarily submitted to extra FDA approval. Other tests are being validated by individual medical labs or university researchers.

In general, these tests aren't reliable enough for individuals to act based on the results. And researchers say, even if you were certain you had antibodies to the coronavirus, it's still unknown if that protects you from getting sick again. Still, these tests can provide good information about rates of infection in a community, where errors in an individual result have less impact.

How quick is it: These tests generally produce results in a few minutes, based on a drop of blood taken from the finger. Some research labs use a more sophisticated antibody test, called an Elisa (Enzyme-linked immunoassay) that are more accurate but are not as widely available.

[Hemmingway]

There is a lot of information out there and probably more bad than good. This popped into my mail yesterday and I thought it explained a lot of things really well:

 

Why Corona Virus Is So Confusing

[camoman1234]

"And researchers say, even if you were certain you had antibodies to the coronavirus, it's still unknown if that protects you from getting sick again."

Could we not assume that one would be protected...? IgG should not change from flu to MMR, etc...I agree with the crappy test out there. We are solicited weekly for these at the clinic. 

[ventana]

31 minutes ago, camoman1234 said:

"And researchers say, even if you were certain you had antibodies to the coronavirus, it's still unknown if that protects you from getting sick again."

Could we not assume that one would be protected...? IgG should not change from flu to MMR, etc...I agree with the crappy test out there. We are solicited weekly for these at the clinic. 

correct.  AB test does NOT confir immunity

 

Hep C AB and HSV come to mind.  AB only proves past exposure

 

then don’t forget the test likely is positive for corona virus and not specific to covid-19.   It is just a money grab folks.  Bad medicine.  Don’t endorse it.  

[WeBuyAndSellJunk]

I am not here to say these tests are perfect or ready, but coronaviruses don’t lie dormant or sequestered from the immune system like hepatitis or HSV. When the evidence isn’t available, we should at least rely on the basic sciences to bolster claims. Other coronaviruses generate immunity for 2-4 years after infection. Even in the setting of asymptomatic exposure and a weaker immune response, the general theory is that memory T/B cells are stored and would provide a quicker and more robust response to reinfection (provided there isn’t some crazy mutation). 
 

The differential rates of antibody positivity geographically also lend some credence to their specificity for COVID-19. Rates in the California FB study for seroprevalence were ~3%, while rates for the NY study were ~20%. That superimposes well on to the backdrop of known infection prevalence, respectively.
 

Like I said before, this needs rolled out in an already high risk group and not to the general public. High risk group X can’t really avoid exposures, but we can certainly then study them for PCR confirmed infection rates versus their already known antibody status. The research wouldn’t even take very long in a hot zone, given that we have some data on average rates of healthcare worker COVID contraction. 
 

I really can’t wait for some data on convalescent serum treatment also. Some of these antibody tests measure the exact same antibodies that we are using as neutralizing antibodies in therapy. 

Edited May 5, 2020 by printer2100

[ventana]

This is just simply NOT ready for prime time

 

you can hedge and qualify, but NONE, not one, of the tests have been independently verified.  Worse then not having a test is having a bad test

 

As for the Hep C comparison, we really don't know what covid-19 does, that is the issue....

 

lets not mistake creative marketing for EBM - remember the companies have a vested interest in making you think the test works so you buy it and they make money.  That is all this is....  nothing more till they get validated by an independent agency

 

I do agree that we need to study this, and this should be in controlled studies on high exposure groups - ie front line health care workers....  but the IRB needs to be involved, and we can't loose the purity of studies and data just because this is a scary infection - it is more important to have good data.....  simply believing something  might work or be useful does not make it so (but the company selling the test will try to make you think so)

[UGoLong]

Here's the deal: each of us gets to live in our own time with whatever knowledge is known. It would be great to live in 50 years -- when even more EBM will be known -- but we don't.  Instead, each of us is the captain of his or her own ship and is forced to make decisions every day based on incomplete information.   

As far as antibody testing goes, I'm in my 70s and suddenly find myself mostly sitting at home. I'm not rounding in hospitals like I did until March. And I'm not riding a couple of times a month with EMS (including into two state prisons) like I also did until March. Fortunately I'm half-time PA faculty and can still teach, only now in my pyjamas (if I wanted to). And today I even went on a rare outing to the grocery store (we pick up these days). I zipped through it like a jewel thief to get Mothers' Day cards. 

Also today I went to a recognized lab and had a vial of blood taken for a COVID-19 antibody test. I don't know yet what I'm going to do with the results, but I'll sort that out when they're back. My hope is that I can go back to  my life and contribute. Maybe sooner, maybe later: the captain of my ship hasn't decided yet. My ship and I are experimentalists at heart: I was a subject in the Salk polio vaccine trials in the '50s,  and a trial subject again -- 4 years ago -- when I had lymphoma. That's a long history of trying stuff (but not bleach...my ship and I aren't stupid).

My point is that each of us has to take our best shot -- often with incomplete information. My "captain" is in the same storm as the rest of you, but on his own ship. Let's honor that in each other.

 

Edited May 5, 2020 by UGoLong

[GetMeOuttaThisMess]

And to think that I only had a dinghy all those years.  Figures.

[bluiz1997]

The Roche test appears promising at least from an accuracy of exposure standpoint.  As always with any test I always consider what the utility of the results will be.

[Mayamom]

14 hours ago, UGoLong said:

'm in my 70s and suddenly find myself mostly sitting at home.

Good for you!! Sound like it is much deserved.  I'm hoping to be sitting home more sooner than 70

[UGoLong]

As a follow up, my antibody test was negative so I am very unlikely to have had COVID-19. I probably won't be rushing out to become a 70+ year old casualty at this point. It cost $130, but I learned something.

Edited May 7, 2020 by UGoLong

[ventana]

6 hours ago, UGoLong said:

As a follow up, my antibody test was negative so I am very unlikely to have had COVID-19. I probably won't be rushing out to become a 70+ year old casualty at this point. It cost $130, but I learned something.

maybe you did, maybe n ot

 

1:5 is wrong by their data - 20% chance

[UGoLong]

maybe you did, maybe n ot
 
1:5 is wrong by their data - 20% chance

Knowing something with even 80% certainty is clearer than many of the things we have to navigate with in life.


Sent from my iPad using Tapatalk

[GetMeOuttaThisMess]

This statement is nothing more than a fun exercise for those who enjoy statistics.  Is the 80% value mentioned above with regard to a negative test result in a patient with unknown infectious status an indicator of positive predictive value, negative predictive value, test sensitivity, or test specificity?  It's VERY important to understand the difference between these for any test.  No one needs to actually respond but only mention it as food for thought.

Edited May 8, 2020 by GetMeOuttaThisMess