World 400 metres champion Salwa Eid Naser has had anti-doping violation charges dismissed by a World Athletics tribunal.

The 22-year-old, who won gold in Doha last year with the third-fastest time in history of 48.14 seconds, was provisionally suspended in June after being charged with four whereabouts violations.

She was charged with a filing failure dated to March 16 last year, effective of January 1, and three missed tests on March 12, 2019, April 12, 2019 and January 24, 2020.

Naser admitted to missing three drug tests but insisted it was "normal" and "can happen to anybody" and made it clear she has "never been a cheat".

One of the four charges was dismissed because the doping control officer, confused by the numbering of the apartments where Naser lives, accidentally knocked on a storage-room door rather than her residence.

World Athletics said "it would be wrong to be critical" of the official as he "committed to do everything possible to locate and test the athlete", including returning to the address later that day before seeing if she was present at the Bahraini National Stadium.

Because the other missed tests were not within a 12-month period, Naser has not violated anti-doping rules.

However, in its ruling, the tribunal warned Naser that her missed test in January 2020 still stands against her and strongly advised that she seeks advice in using the Anti-Doping Administration & Management System (ADAMS) to prevent future complications.

"This was a case very much on the borderline, and we hope the athlete will learn from the experience and heed the AIU's warnings," the tribunal said.

The AIU has 30 days in which to appeal against the decision at the Court of Arbitration for Sport (CAS).