Red Cross and covid antibody testing

[Terabith]

I was looking at my blood donation app to try and figure out when my next appointment is, and I saw that at my last donation (the first since I was vaccinated), I tested as "reactive" to covid antibodies.  I'm assuming this is from vaccination?  At the time I donated, we were still being super duper careful, nobody had been sick, weren't going many places indoors and masking always, etc.  

I mean, if it was now, I'd shrug and say we were probably exposed on this trip, where NOBODY has masked and we've been staying in hotels and eating indoors and what not.  Everyone in our family is fully vaccinated.  

I just didn't know if vaccination gave you antibodies that the Red Cross tests for.

[PeterPan]

36 minutes ago, Terabith said:

I tested as "reactive" to covid antibodies.  I'm assuming this is from vaccination? 

https://www.nytimes.com/2021/06/20/health/covid-vaccine-antibody-test.html

Do your results say what antibodies they were looking for?

Edited June 24, 2021 by PeterPan

[Terabith]

1 minute ago, PeterPan said:

https://www.nytimes.com/2021/06/20/health/covid-vaccine-antibody-test.html

Do your results say what antibodies they were looking for?

Nope.  Just "reactive."  Previous donations, from before I got vaccination, just said, "Negative."

[Ottakee]

From the vaccine.

[Katy]

It's from the vaccine.  I'm not sure where everyone got the idea that the antibody tests were different for vaccine vs virus.  I'm under the impression from the pharmacist in the family they use the same test for both. It looks a bit like a pregnancy test only uses blood.

DH's Red Cross recently notified him he would no longer be getting notifications of antibodies since he was vaccinated.

[vonfirmath]

13 minutes ago, Katy said:

It's from the vaccine.  I'm not sure where everyone got the idea that the antibody tests were different for vaccine vs virus.  I'm under the impression from the pharmacist in the family they use the same test for both. It looks a bit like a pregnancy test only uses blood.

DH's Red Cross recently notified him he would no longer be getting notifications of antibodies since he was vaccinated.

Hrms. Because mine has come back negative twice since being vaccinated.

[TravelingChris]

1 minute ago, vonfirmath said:

Hrms. Because mine has come back negative twice since being vaccinated.

Because it depends on which test is used.  One of the tests doesn't measure vaccination effectiveness.  I know I read an article last week about which tests are good for checking antibodies in vaccinated people and a lot of the more popular ones aren't.

[KSera]

16 minutes ago, Katy said:

It's from the vaccine.  I'm not sure where everyone got the idea that the antibody tests were different for vaccine vs virus.  I'm under the impression from the pharmacist in the family they use the same test for both. It looks a bit like a pregnancy test only uses blood.

DH's Red Cross recently notified him he would no longer be getting notifications of antibodies since he was vaccinated.

 

Just now, TravelingChris said:

Because it depends on which test is used.  One of the tests doesn't measure vaccination effectiveness.  I know I read an article last week about which tests are good for checking antibodies in vaccinated people and a lot of the more popular ones aren't.

Right. This. From the FDA on this:

• Be aware that vaccines trigger antibodies to specific viral protein targets. For example, currently authorized COVID-19 mRNA vaccines induce antibodies to the spike protein and not to nucleocapsid proteins that are likely detected only after natural infections. Therefore, COVID-19 vaccinated people who have not had previous natural infection will receive a negative antibody test result if the antibody test does not detect the antibodies induced by the COVID-19 vaccine. If you are considering antibody testing in vaccinated individuals, follow the Centers for Disease Control and Prevention’s guidelines for antibody testing. For more information about antibody test performance visit EUA Authorized Serology Test Performance.