NAIROBI (REUTERS) - Olympic marathon champion Jemima Sumgong has been handed a four-year ban by Kenya's anti-doping agency (ADAK) after testing positive for the banned blood-booster erythropoietin (EPO), officials said on Tuesday (Nov 7).

Officials said Sumgong, who became the first Kenyan woman to win an Olympic marathon title when she struck gold in Rio last year, had failed an out-of-competition test in April, days before she was due to defend her London Marathon title. Her four-year ban has been backdated to April 3.

The matter was taken to the Sports Disputes Tribunal by ADAK, as recommended by the World Anti-Doping Agency (WADA) code.

The ruling said that the athlete owned up to her "unfortunate offence and unintended mistake". She did not request that her B urine sample be tested after her A sample was returned from Lausanne.

The 32-year-old's claim that she failed the test after undergoing treatment at a Kenyan hospital for an ectopic pregnancy was rejected as "not authentic" by the tribunal, as the hospital in question denied treating the athlete.

Sumgong became Kenya's latest high-profile athlete to fail a drugs test after former Boston and Chicago Marathon champion, Rita Jeptoo, also tested positive for EPO in 2014 and was banned for four years.

Up to 40 athletes from the east African nation have failed tests in the past five years.