Reigning world 100 metres champion Christian Coleman has said he may be hit with a suspension which could rule him out from next year's Tokyo Olympics following a violation of anti-doping whereabouts regulations.

In a lengthy statement on Twitter, the 24-year-old American sprinter said he had been notified by the Athletics Integrity Unit (AIU) that he had missed a drug test on 9 December, 2019.

According to Coleman, he was out Christmas shopping at the time of the test and was "ready and available" to take it if he had received a phone call from the official.

A copy of the AIU's Unsuccessful Attempt Report shared by Coleman said "No phone call was made per client instructions".

"I've been contacted by phone literally every other time I've been tested," Coleman wrote in his statement.

"Literally, IDK (I don't know) why this time was different.

"I was more than ready and available for testing if I had received a phone call I could've taken the drug test and carried on with my night. I was only made aware of this attempted drug test the next day ... when I got this failed attempt report out of nowhere." 

Coleman won gold in the 100m at the World Athletics Championships in Doha, Qatar, last September. He said that this violation might result in a suspension due to two other recent incidents.

If an athlete accumulates three missed tests within a 12-month period, they can incur a suspension of one or two years.

Coleman added: "The other two (were) a missed test on January 16th, 2019 and a filing failure on April 26th, 2019.

"I take responsibility for missing the USADA agent on January 16th, 2019 because I was at the weight room. But I think the attempt on December 9th was a purposeful attempt to get me to miss a test.

"I have never and never will use performance-enhancing supplements or drugs. I am willing to take a drug test every single day for the rest of my career for all I care to prove my innocence."

The AIU has been approached for comment.