Ukraine's Olga Abramova has been provisionally suspended by the International Biathlon Union (IBU) after failing a drug test for a banned substance that was only added to the banned list at the start of 2016.
The Ukrainian Biathlon Federation confirmed Abramova tested positive for the metabolism booster meldonium while competing in the World Cup series.
She tested positive at Ruhpolding in Germany on January 10 nine days after the substance was officially added to the World Anti-Doping Agency's banned list.
The IBU had announced last week that an athlete had been provisionally suspended following a positive test for meldonium but did not identify the competitor.
Abramova told Ukrainian newspaper Segodnya she had taken meldonium, also known as mildronate, for a heart problem.
She claimed it was prescribed by her doctor but she stopped using it three weeks before it was banned.
It stayed in her system, however, she claimed.
The 27-year-old was born in Ulyanovsk Oblast and originally competed for Russia.
She switched allegiance to Ukraine in 2012, however, believing it would be easier to make their team.
Abramova's best performances were as members of Ukraine's relay team, which finished third in World Cup races last season in Antholz and Hochfilzen last December.
The IBU have said they will not comment on the case until the process is completed.