Rafael wrote that Browne's manager Matt Clark and promoter Ricky Hatton did not respond to messages from ESPN.com seeking comment.
Browne tweeted this morning: "I don't understand today's news, and I'm seeking legal advice..."
Browne's 10th-round knockout victory over Chagaev in Grozny, Russia, came after he was knocked down by the Uzbekistan fighter in the sixth round. It appeared to be a triumph over adversity for the former nightclub bouncer and his success was celebrated by Kiwi heavyweight Joseph Parker, who tweeted his congratulations.
Parker, who will fight Carlos Takam on May 21 - probably in New Zealand - in an IBF title eliminator bout, is ranked 11th by the WBA but is likely to move up should Browne fail his B sample. The latest WBO rankings have Parker ranked at No1 behind champion Tyson Fury, putting the Kiwi ahead of fighters such as Anthony Joshua and Wladimir Klitschko.
Duco Events, the promoters of Parker released a statement this afternoon.
"We don't want to see any drugs in boxing. We will wait for the results of the B sample to come in before making any further comment."