Horse trainer Mark Riley's three-year ban has been overturned after the Victorian Supreme Court cleared him of a doping charge.

Mr Riley was accused of administering a prohibited substance to his horse Gold For Kev after a set of blood tests found evidence of alkalising agents above the limit permitted by the rules of racing.

He appealed against a ruling by the Racing Appeals and Disciplinary Board that banned him for three years.

The Victorian Supreme Court heard racing stewards took samples from Gold for Kev to two laboratories following a race at Sandown Racecourse in July 2014.

According to the judgment by Victorian Supreme Court Justice Kevin Bell on Thursday, both labs adjusted their findings for measurement uncertainty, leading to different results.

One found the concentration of total carbon dioxide in the horse's blood was above the allowable limit, while the second found it was below it.

"The result reported by one laboratory was that a prohibited substance was present in the blood in a concentration just above the maximum level, but that result had been rounded-up," Justice Bell said.

Mr Riley took the matter to the Supreme Court after an earlier appeal to the Victorian Civil and Administrative Tribunal upheld the Racing Appeals and Disciplinary Board's decision.

Justice Bell exonerated Mr Riley of the doping charge.

He said the rules did not permit a disqualification to be imposed upon the basis of rounded-up test results.

"The scientific evidence was incapable of supporting a finding of guilt," Justice Bell said.