The latest ITF figures state that the number of blood tests carried out in pro tennis has increased more than four times in the last year.

Blood tests, which are considered to be more revealing than urine tests, rose from 187 in 2012 to 813 in 2013, with 449 held out of competition and 364 taken during competition.

The total number of blood and urine tests on players rose from 2,185 in 2012 to 2,752 last season. There were 1795 urine tests in competition and 144 out of competition, according to the ITF.