Antibody Tests - experiences, thoughts? ?

I had an antibody test last year (work required it, no idea why). I had none. This was before the vaccine.

I’ve had two, one in July 2020 and one in March 2021, both were positive.

I purchased a test kit on line from Lloyd's pharmacy, as I am on immunosuppressants and wondered whether the vaccine had worked for me. I was delighted to find that I had the highest level of protection, but am aware that there is a slight chance of a false positive result. However, it hasn't changed the precautions I take.
onlinedoctor.lloydspharmacy.com/uk/coronavirus-covid-19-testing/covid-19-antibody-test-kit

I've had two antibody tests and just ordered a third.

Of the first two, one was via Testing for All (I paid for it) and involved taking a small blood sample and posting it off and the second was organised as part of of a Covid study (dried blood spot). Both tests, requiring a finger prick, were taken at least 3 weeks after my 2nd Covid vaccination and both were negative.

I am aware of two different types of Covid antibody tests:-
Anti-N (nucleocapsid) tests show if you have had Covid and have developed immunity as a result.
Anti-S (spike) tests detect antibodies produced through Covid infection and vaccination.

As I have not had Covid, I ensure that I use the Anti-S tests.

The test I have ordered for this week is to check whether the combination of the 3rd vaccination and my current antibody replacement therapy has changed my negative status.

If I test positive with a reasonable amount (test is quantitative) of Covid antibodies this time, I will be pleased and may review my self-isolation regime.

If I still test negative, I will have to carry on as I have been.

Either way, I will contact my Haematologist, Immunologist and GP to let them know of my status.

I did one, a year ago before vaccinations were rolled out. I’d had Covid, mildly, the previous March and had recently isolated due to close family members having Covid. At that time I did not catch it, so I wondered about antibodies.
The results did show I’d got antibodies, but I remained cautious. Now I’ve had my 3 jabs, I’m hoping the antibodies are boosted, but I’m still reasonably cautious.

I haven't done one, but would like to know if I have antibodies.
I asked my GP and rheumatologist, who said the only way to get them done in Scotland, is if you are part of a study.
I may consider getting a private one.

We have been chosen at random by the ONS to give swabs every month (been doing it now for 18 months) and for the past few months give a sample of blood each month to be tested for antibodies - each test has come back as positive for antibodies. It hasn't really changed my behaviour, although I suppose, rightly or wrongly, I am a little less worried about catching coronovirus, as I know I have antibodies.

Yes, I had a test a month or two after the pandemic started and long before vaccines were available.

The result showed no antibodies to the coronavirus which was taken as a sign that I had not had it, although I was wretchedly ill for a week at the start of the pandemic.

I've done four. Two were requested by Biobank as part of a study, and each showed that antibodies were present, though didn't specify whether from infection or vaccine. The third one was sent to me three days after my positive Covid test in October, and produced the same result. The fourth one was sent a few weeks later and the result said that this time it "detected antibodies that are made after an infection, and also antibodies that could have been caused by a vaccine".

To answer your last question, it was good to have confirmation that my vaccines had caused antibodies, but it didn't change my behaviour in any way.

I find the science of this fascinating.