LOS ANGELES -- Standout UFC fighter Cristiane "Cyborg" Justino has potentially violated the mixed martial arts promotion's anti-doping policy.
The UFC announced Justino's apparent failure of a doping test Thursday.
The U.S. Anti-Doping Agency, which administers the UFC's anti-doping efforts, told the promotion that Justino was flagged for an out-of-competition test Dec. 5. USADA will go through its review process before announcing any sanctions or suspensions.
On her personal webpage, Justino wrote she tested positive for a diuretic she is taking as part of a therapeutic treatment due to medical issues related to her difficult weight cuts before bouts. She hopes to get a retroactive therapeutic use exemption for the substance.
"For my fans who are disappointed in the news, I am sorry," Justino wrote. "You can feel confident that the substance they are inquiring about is not for performance enhancing use, and is needed for my specific treatments. Feel confident that I am a clean athlete."
Justino (17-1) is considered one of the world's top pound-for-pound fighters, and the UFC recently announced the formation of a 145-pound women's featherweight division largely to provide a platform for Justino at her optimal weight. After winning titles in the Invicta and Strikeforce promotions, Justino won her first two fights in the UFC earlier this year.
Justino was stripped of her Strikeforce featherweight title in 2012 after testing positive for steroids. The Brazilian-born U.S. citizen served a yearlong suspension before returning to the sport and receiving derision for her steroid use from other top fighters, including Ronda Rousey.
The UFC hoped to put her in the featherweight division's inaugural title fight on Feb. 11, but Cyborg turned down the bout, saying she didn't have enough time to prepare. Instead, former bantamweight champion Holly Holm will take on Germaine de Randamie for the new 145-pound belt at the Barclays Center in Brooklyn.