Eddie Hearn claimed Dillian Whyte and Oscar Rivas were both cleared to fight amid a report the Brit tested positive for a banned substance before the bout.
Whyte claimed the WBC interim heavyweight title with a unanimous-decision win over Rivas in London on Saturday.
But Boxing Scene reported on Wednesday that Whyte had "tested positive for one or more banned substances" prior to the fight, which was allowed to proceed by the British Boxing Board of Control (BBBofC).
Hearn, Whyte's promoter, did not say if the 31-year-old had tested positive, but confirmed he was cleared to fight.
"Further to reports I can confirm that both Dillian Whyte and Oscar Rivas were subject to extensive VADA [Voluntary Anti-Doping Association] and UKAD [UK Anti-Doping] testing for their bout," Hearn wrote on Twitter.
Further to reports I can confirm that both Dillian Whyte and Oscar Rivas were subject to extensive VADA and UKAD testing for their bout. Both fighters were cleared to fight by both bodies and the BBBofC
— Eddie Hearn (@EddieHearn) July 24, 2019
"Both fighters were cleared to fight by both bodies and the BBBofC."
Whyte claimed a dominant win over Rivas, with two judges scoring it 115-112 in his favour and a third 116-111.
