Irish 200m champion Steven Colvert has strenuously denied using performance-enhancing drugs despite testing positive for EPO.
The Crusaders sprinter has been withdrawn from the Irish team for the European Team Championships in Estonia this weekend.
He had been due to compete in the 100m, 200m and 100m relay.
The positive result for EPO, a drug which boosts the level of oxygen-carrying red cells in blood and can improve endurance, will likely result in a two-year ban, although Colvert, who insists he has only ever taken multivitamins and iron will demand the testing of the B-sample.
"It all just feels like a really bad dream or a horrible prank," the 23-year-old told the Examiner.
"I firmly believe there has been some sort of error or false positive.
"I'm part of a programme in which they keep all of my samples for 10 years and I'm happy to go back and let them test every single sample provided.
"I'm flabbergasted by the findings," he said. "If it was pseudoephedrine or a stimulant that's easily found in things like Lemsip then I could try and remember had I inadvertently taken something.
"I'm coming forward with this finding because I have nothing to hide and I'm happy to have complete transparency into the whole ordeal."
DCU student Colvert only missed out on competing at the London 2012 Olympics by .02 of a second.
"Athletics Ireland has been informed by the Irish Sports Council (ISC) that an Irish athlete has tested positive for a banned substance," the organisation said in a statement.
"In following the strict procedures applying to an adverse analytical finding, the athlete in question has been informed and has the opportunity to have a “B” sample tested and to attend a hearing with the ISC to present the athlete’s case.
"Athletics Ireland will not comment further until all elements of due process associated with the anti-doping programme In respect of the athlete are completed."