The NHL retested some teams for COVID-19 on Wednesday after what it believed were false positive results from one U.S.-based lab on Tuesday.

The St. Louis Blues were one of at least two playoff teams impacted, both of which were scheduled to play Wednesday night.

"We have discovered discrepancies in Covid test results relating to multiple players," Doug Armstrong, the Blues' president of hockey operations and general manager, said in a statement. "We have been in touch with and are working with the league to address these discrepancies with additional testing and expect to have further information later this afternoon. The league will provide a further update when we have more information."

The Blues were the only active team to have players on the NHL's COVID-related absences list Tuesday. Forward David Perron, their leading scorer, missed Game 1 of their series with the Colorado Avalanche on Monday. Forward Nathan Walker and defenseman Jake Walman also were on the list.

Walman was a notable absence because the Blues said he was the rare "breakthrough case" of COVID after vaccination. He was placed on the list May 12 after the team asked for additional testing.

An NHL source said the teams hoped for a resolution of the testing issue by the afternoon.

There is still consistent testing of players in the Stanley Cup playoffs, but the NHL announced earlier in May that it would be easing COVID restrictions for U.S. teams once 85% of their traveling party was fully vaccinated. Those teams could have players gather in groups and not undergo PCR testing on off days, among other perks.

Well over 100 NHL players missed time in the regular season after going on the NHL's COVID-related absences list. Multiple teams had their seasons interrupted by COVID outbreaks, including the Vancouver Canucks, who were scheduled to finish their regular season on Wednesday, the same day as Game 3 of the first round for Boston and Washington.