There are always some tests for Lyme disease that are positive, and you see no evidence of Lyme. The person doesn’t seem to have had Lyme before. They don’t have a rash. They’re not ill. In that case, I work with them and evaluate  whether they should be treated for a limited period, like three to four weeks, just in case there’s a tick-borne illness present. Yes, it could be a false positive, but I’d hate to have it turn into a true positive over time. Other doctors might choose to wait.