There are a number of commercial ELISA kits available, but there is little validation data available to identify the effectiveness of these tests. WHO do not yet appear to have any information on ELISA tests and FIND are currently undertaking validation studies on lateral flow assays (LFAs) and ELISA tests. This began in mid-May and results will be published on their website at the following link.
The American CDC has published antibody test guidelines.
Running the test
National COVID scientific advisory panel Validation paper | Test performance evaluation of SARS-CoV-2 serological assays