Former super middleweight world titleholder Lucian Bute, who tested positive for a banned substance after his draw against titlist Badou Jack on April 30 at the D.C. Armory in Washington, D.C., will have his “B” sample tested on Thursday, the WBC announced.

Bute’s “A” sample tested positive for the banned substance ostarine (also called enobosarm), which is supposed to increase stamina and recovery ability.

Ostarine has been on the World Anti-Doping Agency’s banned list since 2008.

“The Washington D.C. Boxing and Wrestling Commission has been handling the process related to Lucian Bute’s positive anti-doping test result for Ostarine,” the WBC said on Wednesday. “The WBC and the D.C. commission have communicated frequently about that case. The D.C. commission arranged for the opening of Mr. Bute’s ‘B’ sample, which will take place on Thursday.

“Mr. Bute has designated his representatives, who will attend the opening of the ‘B’ sample container, consistent with the WBC rules & regulations. More information about this case will be made available in days to come.”

Following the positive test, Bute denied taking any banned substance.

“I am surprised and sad about that news,” Bute said. “I can’t understand how the test could have been positive. I have been tested exhaustively since I was world champion and never tested positive. I have never taken anything prohibited. I trust every member of my team and I am convinced when the B sample will be tested it will prove me right and will turn out negative.”

Should the B sample also test positive, Bute (32-3-1, 25 KOs) faces a probable fine and suspension. The result of the fight — a majority draw in which two judges scored the bout 114-114 and one had Jack (20-1-2, 12 KOs) winning 117-111 — would also be changed to a no-decision.

Bute, 36, of Montreal, held a 168-pound world title from 2007 to 2012 and made nine successful defenses.

Whether the result remains a draw or is changed to a no-decision, it won’t change the plans of the 32-year-old Jack, a native of Sweden living in Las Vegas. He is slated to face England’s James DeGale (23-1, 14 KOs) in a fall world title unification fight. DeGale retained his version of the title by unanimous decision against Rogelio “Porky” Medina on the Jack-Bute undercard.