I wouldn't put as much faith in current antibody tests, especially where "In a low prevalence area for previous Covid-19 infection, which is most of the country, a positive antibody result could be a true positive or a false negative."[1]
This is a new test from Karolinska Institute that can only have false negatives, not false positives.
With that said they had to retract the test results but that was due to other reason (accidentally including people who gave blood due to being infected).
Let’s see the research and judge by then. I’ve seen published study from Uppsala that tested and confirmed antibody tests with high degree of accuracy 99%+, but had 1 false positive related to cross reaction to another corona virus but they had no details on the sample input or the kind of corona virus is cross reacted with, and hence no way of knowing the accuracy. Lots of bad science being performed these days so I’ll be skeptical until I read the results myself.
Is that even possible to have a serological test that can't give false positives? Field contamination etc would seem to be something that can't be prevented.
The specificity of a test is a property of the test itself, not of the circumstances in which it is applied.
If a test has a 100% specificity, and you give it a sample that has been contaminated with the virus, the fact that it registers a positive result is not an error.
> Karolinska University Hospital and Karolinska Institutet have collaborated to produce a new antibody test in the fight against covid-19.
> - We are happy to have a test that we know is okay. It is not 100 percent sensitive, it has sensitivity of 70-80 percent. Some will test negative even though they have had it. But no one will test false positively. Those we have tested that should be negative have been, says Jan Albert.
(Google Translate translates chief physician to consultant for some reason but other than that the translation seems fine)
[1] - Michael Osterholm https://www.cnn.com/2020/04/21/opinions/bergen-osterholm-int...