I also wonder how effective these anti body tests are, and their false negative rate. In actual trials, has a single one actually been shown to work reliably?

I also wonder how effective these anti body tests are, and their false negative rate. In actual trials, has a single one actually been shown to work reliably? Here in the UK there's a new story every week about how yet another antibody test has been withdrawn or rejected by PHE because it wasn't accurate.