Lawyers representing Ustyugov have confirmed the CAS Anti-Doping Division has found in favour of the International Biathlon Union (IBU).

The Russian was charged by the Biathlon Integrity Unit earlier this year, regarding abnormalities in his Athlete Biological Passport in the period between January 2010 and February 2014.

The case reportedly relates to abnormal levels of haemoglobin.

Lawyers for Ustyugov say they argued the 35-year-old has a "naturally high level of haemoglobin due to a genetic mutation".

His defence said "evidence was presented that both of Mr. Ustyugov's parents have a high natural level of haemoglobin as well as a full breakdown of Mr. Ustyugov's genome, in which a key mutation was isolated that impacts haemoglobin levels."

Evidence was also presented showing his haemoglobin remained at a consistently high level in IBU tests as late as 2017.

Lawyers for Ustyugov claim this was also shown in additional samples presented in 2020, taken years after his retirement in 2014.

Ustyugov's defence added that the biathlete is "prepared to give further blood samples to confirm that his natural haemoglobin level is higher than in the general human population should anyone wish to confirm this fact", adding that he has never had a positive doping test throughout his career.

Ustyugov is set to lose results earned at the Vancouver 2010 and Sochi 2014 Winter Olympics due to the decision, with the sanction set to stretch from 2010 to 2014.

Ustyuov, who is now retired, also won mass start gold and relay bronze at the Vancouver 2010 Winter Olympics.

He also won gold in the men’s 4x7.5 kilometres relay event at Sochi 2014.

The gold medal is already in doubt due to Ustyugov being sanctioned earlier this year by the IBU Anti-Doping Hearing Panel in a separate case based on analysis of Moscow Laboratory data.

The IBU said Ustyugov had "committed an Article 2.2 ADRV [anti-doping rule violation] under the 2012 IBU Anti-Doping Rules" by using the prohibited substance oxandrolone.

He was handed a two-year ban.

The case is currently being appealed at CAS.

The hearing was due to take place last week, but was postponed.

Should the sanction stand,  his team mates Anton Shipulin, Dmitry Malyshko and Alexei Volkov also facing losing their medals.

Silver medallists Erik Lesser, Daniel Böhm, Arnd Peiffer and Simon Schempp of Germany would be in line for an upgrade to gold, with Austria’s Christoph Sumann, Daniel Mesotitsch, Simon Eder and Dominik Landertinger moving to silver.

Tarjei Bø, Johannes Thingnes Bø, Ole Einar Bjørndalen and Emil Hegle Svendsen would move onto the podium, with the Norwegians receiving bronze.