Having a Lyme literate doctor, being in the right stage of infection for the test given, being given the right test, etc. https://www.columbia-lyme.org/diagnosis You can read a bit about it here. If you don't have joint inflammation and unexplained exhaustion I wouldn't worry about it. But if that ever shows up, look for a Lyme literate doctor, don't go to a regular one they are zero help.