World Championships 2017: Three 'adverse' London findings investigated
Three "adverse" doping samples from the World Athletics Championships are being investigated by the Athletics Integrity Unit.
None of the samples belong to athletes who won medals in London.
More than 2,000 blood and urine tests were conducted in a 10-month spell before the Worlds, with a further 1,513 samples taken from 991 athletes in the build-up and during the event.
The AIU said there was a "strong, positive reaction" from athletes.
The independent organisation came into operation in April and handles aspects relating to misconduct within the sport, replacing the International Association of Athletics Federations' (IAAF) former anti-doping department.
Part of the AIU's remit is to restore trust in athletics following, predominantly, the McLaren report which made claims of state-sponsored doping in Russia.
"It was hugely satisfying to see that athletes have a real thirst to gain knowledge of integrity-related issues and to learn how they can better help uphold the right values of the sport," said the AIU's operational chief Ed Clothier.
"The AIU will build on this."