First, if you're talking about swabbing, then I think you're talking about the test to see whether a person is currently infected with the virus. That's what the article you linked was regarding.
The antibody tests are a different animal. They test to see whether you might have been infected in the past, by looking for antibodies in your blood. So these are blood tests, and, I expect, have less chance for user error.
But also, I think lots of covid antibody tests are not high accuracy even "in theory". It seems the FDA relaxed oversight on companies producing antibody tests: ". . . after being criticized for the fumbled rollout of diagnostic tests during the start of a global pandemic, the FDA swung hard in the other direction, waiving its usual requirements and letting firms rush self-validated [antibody] tests into the market."[1]
So there are antibody tests from over 200 companies out there. Some of these antibody tests are quite accurate, high sensitivity and specificity. Others, not so much.
The antibody tests are a different animal. They test to see whether you might have been infected in the past, by looking for antibodies in your blood. So these are blood tests, and, I expect, have less chance for user error.
But also, I think lots of covid antibody tests are not high accuracy even "in theory". It seems the FDA relaxed oversight on companies producing antibody tests: ". . . after being criticized for the fumbled rollout of diagnostic tests during the start of a global pandemic, the FDA swung hard in the other direction, waiving its usual requirements and letting firms rush self-validated [antibody] tests into the market."[1]
So there are antibody tests from over 200 companies out there. Some of these antibody tests are quite accurate, high sensitivity and specificity. Others, not so much.
[1] https://khn.org/news/hype-collides-with-science-as-fda-tries...