It could happen, but it is extremely rare. It would mean the test has said its detected something that's not there. If you're unsure, you can re-test. Make sure to do all the testing as accurately as possible (if its urine get a sample of the first initial stream and dont start collecting part way through, if its a swab make sure you gather enough on the swab and not just lightly at the opening of the vagina) and do a blood test because that's highly unlikely to give you a false positive.
@May the only test that has a higher chance of being a false positive is hep b. My mom, who has been celibate for a couple years tested positive last year. She got tested two more times three months apart and both of those were negative. Her Dr said sometimes it happens 😯
Oh wow thanks @Kiarra I'll add that to the memory bank of info haha
Rarely. You can get retested though!