The athlete biological passport will be fully effective at the elite level in tennis by September, the International Tennis Federation (ITF) said yesterday.

The passport, which uses blood tests to detect the likelihood of doping rather than testing for specific substances, came into operation in the final quarter of 2013 and covers around 50 of the world’s top players.

If a player’s blood profile deviates beyond accepted parametres, set by WADA, they could be banned, even if they have not failed a drugs test.

The passport is at its most effective once a player has given between three and five blood tests.

“While it is (already) in full operation, its effectiveness is still increasing by virtue of the number of samples that have been collected for every player in the (testing) pool,” Stuart Miller, head of the ITF’s anti-doping programme, said.

“It is based on multiple samples collected over time, which is why that effectiveness needs time to kick in.”

The ITF has been criticised in the past for carrying out a relatively low percentage of blood tests, which are considered the most effective way of catching drugs cheats.