Kenyan long-distance runner Diana Chepkorir has been banned from competition for four years after the Athletics Integrity Unit (AIU) found evidence of blood doping through her Athlete Biological Passport (ABP).
The AIU announced that samples collected from the 23-year-old between June and September 2024 revealed abnormal blood values “consistent with the use of a prohibited substance or method.”
According to the statement, the fluctuations followed a pattern typically seen when an athlete artificially boosts red blood cell levels, prompting the body to subsequently reduce its natural production.
“The sequence of samples displays an ‘ON’ followed by an ‘OFF’ phase pathognomonic for situations where the red cell mass is artificially increased,” the AIU said in its findings.
A panel of three independent experts unanimously concluded that the abnormalities were “likely due to doping,” prompting the AIU to declare an Adverse Passport Finding.
Chepkorir, who is managed by the Netherlands-based agency Volare Sports, denied the allegations and criticised the process. “I received your notice with utmost shock and disbelief… I disapprove of any involvement in any anti-doping violation,” she stated in her response.
However, the AIU dismissed her defence, stating that all testing was conducted at World Anti-Doping Agency (WADA)-accredited laboratories, and that Chepkorir had failed to provide any credible scientific explanation for the irregularities. A formal charge was issued in September, followed by a provisional suspension starting 15 September 2025.
As a result of the ruling, all of Chepkorir’s competitive results from 25 June 2024 onwards have been annulled, including any titles, medals, or prize money earned during that period.
Chepkorir retains the right to appeal the decision before the Court of Arbitration for Sport (CAS) in Lausanne, Switzerland.
She becomes the fourth Kenyan athlete in just one month to be sanctioned by the AIU for doping offences, following bans handed to Roncer Kipkorir Konga, Joyciline Chepngeno, and Charles Kipkurui Langat.