At least 39% of players who played in the English Football League last season were not drugs tested by UK Anti-Doping (Ukad), according to official figures.
Ukad, which carries out testing on behalf of the Football Association, took 1,204 samples from 1,989 players to appear in the EFL in 2015-16.
From 550 players to play in the Premier League, 799 samples were taken. There were no tests in the National League.