The number of positive doping tests in 2015 has risen marginally compared to the previous year, the World Anti-Doping Agency (WADA) said. 
Releasing is 2015 report, WADA said that 303,369 doping tests were conducted worldwide last year, up 7.1 per cent from 283,305 in 2014. 
Of those, 3,809 tests (1.26 per cent) were positive in 2015, up from 3,153 (1.11 per cent). 
WADA also spoke of a "significant" increase in tests for key substances such as Human Growth Hormone, and that many more blood tests were carried out as well, 21,176 compared to 13,553 in 2014. 
However, recent adverse findings in retests of samples from the 2008 and 2012 Olympics with the latest analytical methods show that more athlete than those caught could have used prohibited substances.

Source: QNA