Jones's initial sample had tested positive for erythropoietin at the U.S. championships in Indianapolis in June. Had the second sample tested positive, the 30-year-old would have faced a two-year ban from the sport.

"I am absolutely ecstatic," Jones said in a statement issued by her lawyer. "I have always maintained that I have never ever taken performance enhancing drugs, and I am pleased that a scientific process has now demonstrated that fact."