Team Sky have taken the decision to take Sergio Henao off their race programme after the Colombian has returned abnormal test results in internal controls. Henao is raised at altitude which may explain the numbers but as a measure of precaution, the team will keep him inactive for at least 8 weeks while he undergoes a testing programme in Colombia.

Sergio Henao has been taken off Team Sky’s race schedule and is set to return to Colombia for an altitude research programme.

The decision was made by the team following its latest monthly governance review, a comprehensive internal process which looks at each rider’s physiological profile.

Team Principal, Dave Brailsford, said: "We have strong monitoring and compliance processes in this team, with the full cooperation of riders and coaches.

“In our latest monthly review, our experts had questions about Sergio’s out-of-competition control tests at altitude - tests introduced this winter by the anti-doping authorities. We need to understand these readings better.

“We contacted the relevant authorities - the UCI and CADF – pointed to these readings and asked whether they could give us any insights. We've also taken Sergio out of our race programme whilst we get a better understanding of these profiles and his physiology.

“We want to do the right thing and we want to be fair. It’s important not to jump to conclusions.”

Sergio Henao was born at altitude in Rionegro, Colombia and lives and trains in the region outside the race season. He returned there in October and had WADA-accredited out-of-competition tests in this period.

Dave Brailsford continued: “Sergio was raised in the mountains, goes back in winter and lives and trains at different levels. We’ve looked as far as we can at the effects of this, but our own understanding is limited by a lack of scientific research into ‘altitude natives’ such as Sergio.

“We are commissioning independent scientific research to better understand the effects of prolonged periods at altitude after returning from sea level, specifically on altitude natives.

“The independent experts are looking to use WADA-accredited laboratories and Team Sky will make the data and findings available to WADA, the UCI and CADF.

“Sergio will help with this programme and we expect him to be out of the race schedule for at least eight weeks. Once we have completed our assessment, we’ll decide on the right steps and give a full update.”