Christian Coleman will not be at the Olympic Games in Tokyo despite his two-year ban being reduced by six months.
The ruling by Athletics Integrity Unit (AIU) was partially upheld by the Court of Arbitration for Sport (CAS) but the negligence was lower.
Coleman produced three failures in a 12-month period at the location provided to anti-doping officials.
The AIU investigation said there was no suggestion that he had ever taken a banned substance.
His ban was reduced because it was judged to be not entirely at fault for one of the three missed tests.
Coleman is the reigning world champion in the 100m and the world record holder in the indoors 60m.