Doha - Asbel Kiprop tested positive for the endurance-boosting drug EPO, the Athletics Integrity Unit (AIU) confirmed on Friday, refuting allegations by the Kenyan track star that his sample might have been contaminated.
Kiprop, a three-time world 1500m champion and 2008 Olympic gold medallist, on Thursday "vehemently denied" doping, suggesting an out-of-competition sample he gave could have been contaminated by two anti-doping agents he suspects might have targeted him for extortion.
The AIU, which deals with doping matters for track and field's governing body the IAAF, responded by saying that 28-year-old Kiprop was notified on February 3 of having tested positive for erythropoietin (EPO).
"On March 16, 2018, Kiprop was charged with violations of the IAAF Anti-Doping Rules and the matter is currently proceeding before the independent IAAF Disciplinary Tribunal," the AIU said in a statement.
"The AIU is satisfied that there has been no mix-up or tampering with the sample and that the sample collected from the Athlete on November 27, 2017 was the same sample analysed by the Laboratory and reported as an Adverse Analytical Finding," it said.
However, the AIU confirmed that the doping control agent had given Kiprop advance warning of the test, an act it described as "extremely disappointing".
But the body argued: "The advanced notice of testing given by the Doping Control Assistant could not reasonably have caused EPO to be present in Kiprop's sample and, as such, the departure does not invalidate the Adverse Analytical Finding. This will ultimately be a matter for the Tribunal to determine."
The AIU also rejected Kiprop's claim that he was offered a "reward" of being an IAAF ambassador on anti-doping in return for admitting to having taken the drug.
Kiprop said on Thursday he had been left "extremely shocked" when informed of the positive test, adding: "I was however very confident the mistake alleging I doped would be noted and I would be cleared. The nightmare has continued.
"I did not dope. I do not labour under the weight of the shame of doping."
The confirmation of the positive test deals a serious blow to Kenyan athletics, with Kiprop one of the biggest names in the country's stellar cast of middle-distance athletes.
Kiprop originally came second in the 1 500m final at the 2008 Beijing Olympics but was upgraded when Rashid Ramzi tested positive for a performance-enhancing drug and was stripped of the gold medal. The Kenyan went on to prove his dominance over the distance with three world titles.
Kenya has been fighting intense criticism of its anti-doping efforts after more than 40 athletes tested positive over the past five years.
Three years ago, Kenya was rated "non-compliant" by WADA before being reinstated prior to the Rio Olympics.