UEFA says some players might go through the European Championship without being blood-tested, despite what it calls the most comprehensive anti-doping programme seen at a major tournament.
On Tuesday the European governing body revealed the details of its anti-doping plans for the month-long tournament at the French anti-doping laboratory where samples will be analysed.
All players from the 24 teams have been in a testing pool since January, Marc Vouillamoz, the UEFA head of medical and anti-doping, explained. But because some national anti-doping organisations (NADOs) don't perform blood collection, "it may be that some players do not have a blood test," Vouillamoz said.
UEFA will, however, carry out targeted doping tests during the tournament from June 10 to July 10, and Vouillamoz said that "it's very unlikely that some players won't be tested at all."
He wouldn't identify which teams haven't been blood-tested at home, but said cooperation agreements signed with all of them facilitated the sharing of players' biological profiles.
UEFA will also keep a close eye on the Russia national team following the country's string of positive meldonium tests in other sports.
"We have been working very closely with UK Anti-doping, who are in charge of monitoring the program in Russia," Vouillamoz said. "Of course we are paying special attention to the Russian team."
Samples collected by the Euro 2016 anti-doping program will be stored for four years and will be available for subsequent retesting.