Chelsea have reportedly expressed their irritation at being the subject of a random drugs test the day before the Blues took on Manchester United in the Premier League.
A handful of players are believed to have been selected by the Football Association's testers during a training session at the Champions League winners' base at Cobham, according to the Daily Mail.
Reports have claimed that the London outfit were not best pleased with the impromptu visit but understood that they were required to provide samples.
The following day, Chelsea suffered a 3-2 defeat to United at Stamford Bridge, which included the dismissals of Branislav Ivanovic and Fernando Torres.
Germany
Switzerland
Hungary
Scotland
Spain
Italy
Croatia
Albania
England
Denmark
Slovenia
Serbia
Austria
France
Netherlands
Poland
Romania
Belgium
Slovakia
Ukraine
Portugal
Turkey
Georgia
Czech Republic