A leak of test data has caused The World Anti-Doping Agency (WADA) to become "very alarmed" about apparent doping from athletes that was discovered in documents that belonged to the International Association of Athletics Federations (IAAF).

According to The Sunday Times, 12,000 blood tests from 5,000 athletes between 2001 and 2012 were leaked and it resulted in the discovery of an "extraordinary extent of cheating" by athletes at the world's largest events.

The revelation stems from a special by German broadcaster ADR/WDR, which released, "Doping - Top Secret: The Shadowy World of Athletics."

The release doesn't mention any names, but it brings some of the London 2012 Olympic results into question and Russia appears to be a primary offender, with 80% of its medals being won by athletes who are under suspicion for doping.

The IAAF said that the documents were released "without consent" and actions could be put forth to follow up on the non-mandated leak.

WADA president Craig Reedie said the organization is "very disturbed by these new allegations... which will, once again, shake the foundation of clean athletes worldwide."

According to BBC, The Sunday Times and ADR/WDR brought in scientists and anti-doping experts Robin Parisotto and Michael Ashenden to review the data and here is what they discovered:

--A third of medals (146, including 55 golds) in endurance events at the Olympics and World Championships between 2001 and 2012 were won by athletes who have recorded suspicious tests. It is claimed none of these athletes have been stripped of their medals.

--More than 800 athletes - one in seven of those named in the files - have recorded blood tests described by one of the experts as "highly suggestive of doping or at the very least abnormal".

--A top UK athlete is among seven Britons with suspicious blood scores.

--British athletes - including Olympic champion heptathlete Jessica Ennis-Hill - have lost out in major events to competitors who were under suspicion.

--Ten medals at London 2012 were won by athletes who have dubious test results.

--In some finals, every athlete in the three medal positions had recorded a suspicious blood test.

--Russia emerges as "the blood testing epicenter of the world" with more than 80% of the country's medals won by suspicious athletes, while Kenya had 18 medals won by suspicious athletes.

--Stars such as Britain's Mo Farah and Jamaican sprinter Usain Bolt recorded no abnormal results.

--Athletes are increasingly using blood transfusions and EPO micro-doses to boost the red cell count.

The IAAF released a statement about the leak.

"The IAAF is now preparing a detailed response to both media outlets and will reserve the right to take any follow-up action necessary to protect the rights of the IAAF and its athletes," the organization said.

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