# How can I tell if I was asymptomatic with COVID? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [January 19, 2022, 5:54pm UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067 "2022-01-19T17:54:23Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [January 19, 2022, 5:54pm UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067/1 "2022-01-19T17:54:23Z")
I’m fully vaccinated and boosted. I gave blood a couple of weeks ago and was sent the results of an antigen test that said that I was positive which meant that I had either had COVID or was vaccinated. This isn’t particularly useful information since I know that I was vaccinated. Is there a test that can tell the difference? ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [January 19, 2022, 6:07pm UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067/2 "2022-01-19T18:07:46Z")
Serum antibody tests which check specifically for viral capsule antibodies would show whether you had been infected, since vaccination only produces viral spike antibodies. I assume most antibody tests focus on spike protein AB detection, for whatever reasons. My understanding is that this is the antibody titer that best reflects prompt immunity. ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [January 20, 2022, 1:04am UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067/3 "2022-01-20T01:04:50Z")
> [@Nars\_Glinley](#): > > I gave blood a couple of weeks ago and was sent the results of an antigen test that said that I was positive which meant that I had either had COVID or was vaccinated. In a previous thread I saw some confusion about “rapid antigen” tests, which some people think is testing for an immune response, but which is actually testing for viral proteins. An “antigen” is a thing your immune system reacts to. In the case of a covid antigen, it’s part of the covid virus. Are you sure that the results of the test you got were testing for immune response and would show a positive for anyone vaccinated? What value is there in testing donated blood to see whether someone is vaccinated? A majority of people are vaccinated, so it’s not like they could do anything useful with a positive result. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [January 20, 2022, 1:52am UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067/4 "2022-01-20T01:52:14Z")
My mistake. It was an antibody test, not antigen. I still don’t see the benefit of it to the vaccinated. ---
**Author:** ![Esprise\_Me](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/esprise_me/32/2947_2.png) [@Esprise\_Me](https://boards.straightdope.com/u/Esprise_Me)\ **Post date:** [January 20, 2022, 4:27am UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067/5 "2022-01-20T04:27:02Z")
Blood donation centers started giving antibody tests instead of movie tickets almost 2 years ago, when there was no vaccine. I’ll admit, I was hopeful for a positive result. Those tests don’t make as much sense anymore, and my local place has switched to a different incentive. ---
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [January 22, 2022, 10:41pm UTC](https://boards.straightdope.com/t/how-can-i-tell-if-i-was-asymptomatic-with-covid/958067/6 "2022-01-22T22:41:52Z")
Any idea what those tests cost? I have been such a bundle of anxiety at the prospect that I might get really sick if infected that I have literally been taking sporadic anti-anxiety meds. OTOH my dad, the now 81-year-old asthmatic, was apparently infected pre-vaccine and had absolutely zero symptoms. If the test isn’t crazy expensive, I might even be willing to pay out of pocket because it would REALLY take a load off my mind if I discovered I’d contracted COVID at some point and never knew.