How did the Bears go from 9 positive COVID-19 tests to practicing? And how did the lab error occur? What you need to know about the NFL's 77 false positives.

Several NFL teams had their weekends disrupted by false positive COVID-19 tests that the league traced to the same New Jersey BioReference lab.

The Bears had nine positive COVID-19 tests from players and coaches that turned out to be false positives. And according to reports around the league, the Jets, Vikings, Steelers, Bills, Browns, Packers, Eagles, Lions and Giants also had spikes in positive tests, with many confirming Sunday afternoon they were false positives.

The NFL had the lab examine 77 positive tests from 11 teams, and all came back negative upon retesting, according to ESPN.

Here's what we know _ and what we don't _ about how those false positive tests unfolded and where the league goes from here.