We are trying to setup a straightforward SPA assay to measure binding of a 3H-labeled ligand to a biotinylated receptor on a TopCount NXT instrument. The counter seems to be sensitive enough, and we do detect binding. However, one incredibly annoying (!!) problem is a build-up of static charge on the plates. This results in random aberrant readings, which are sometimes in 1000s of CPMs. The problem goes away when the plates are left alone for a day or two, but we need to be able to measure much sooner than that. We are using the exact type of plates recommended for this sort of assay; and I cannot find an anti-static version of such plates. I am sure this must be a common issue, so there has to be a solution… What are we missing – any suggestions??