That means that many positives were false positives due to non-specific crossreactivity.

Quacks seized on this and began diagnosing tons of people with chronic Lyme disease based on a not very good test which had positive/negative cutoffs meant to make the assay very sensitive but not specific.

It's a good scam, because people who have false positive test results tend to have them forever so the quack can continue charging a lot of money for cheap treatments forever.