WASHINGTON (AP) — Months into the coronavirus pandemic there are still unanswered questions about the accuracy of tests used to screen Americans. Experts say more data is needed on critical issues, including how many infections tests may be missing. The Food and Drug Administration has authorized scores of tests based on a small number of lab studies. Experts say those measures doesn’t capture how tests perform when used on patients and could contribute to new viral flare-ups due to missed infections. The FDA says its standards are lower due to the current emergency but it has asked some test makers for additional information.