Cardoso was suspended by his team Trek-Segafredo on the eve of the 2017 Tour de France after erythropoietin (EPO) was detected in an out-of-competition test.

Following a process that has taken more than a year, the UCI announced on Thursday (November 15) that he would be banned for four years.

"The UCI announces that the UCI Anti-Doping Tribunal has rendered its decision in the case involving André Cardoso," the body said.

"The Anti-Doping Tribunal found the rider guilty of an anti-doping rule violation (use of erythropoietin) and imposed a four-year period of ineligibility on the rider."

The announcement is said to have come as a "shock" to Cardoso.

In a press release published on his Facebook page, it is claimed that when his B sample was tested by the Swiss Laboratory for Doping Analyses in Lausanne, the lab recorded an inconclusive result, stating that the urine tested was "doubtful but inconclusive regarding the presence of recombinant EPO".

It goes onto say that a negative B sample should override a positive A sample, but because the lab recorded Cardoso’s result as "atypical", it was left open to interpretation by the UCI.

"I'm trying my best not to be angry, but I am extremely disappointed by the confirmation," the 34-year-old in response to the UCI announcement.

"I've been fighting this for 16 months, but from the beginning it was clear that the UCI wanted to make an example of me to create a precedent for sanctioning athletes with an A sample, ignoring due process.

"We saw that when they hired one of the top law firms in Switzerland and just about every medical expert who could help us prove our case.

"Why do that to fight a case that they say was clear cut?

"If it was a simple case, this would have been concluded quickly.

"I would also like to put on the record that the out-of-competition test in question was conducted outside of my designated time slot, and that I opened the door knowing who was there.

"Had I been involved in anything illegal, I could have simply stayed inside without fear of repercussions. 

"I know that this doesn't prove my innocence, but I would like to think that it suggests how open and involved I have always been in the fight against doping."

He added: "The fact that I know this has caused pain to my family, friends and former team-mates only adds insult to injury because I feel responsible for their distress even though I did nothing wrong.

"With that said, I would like to apologise again and tell them that they are right to put their faith in me and that I am deeply sorry for the fact that they've been dragged into such a stressful and saddening mess.

"At this point, I need to consider all my options, but I intend to raise funds for a legal battle and to get to continue to work to prove my innocence.

"For me, this is also a discussion about fairness because unless someone has the financial resources of a top rider, it's impossible to fight."

Cardoso has also commissioned impartial examinations from Douwe de Boer, an anti-doping expert based in The Netherlands, to investigate what triggered the UCI's Adverse Analytical Finding.

"Sport doping control is being performed to protect the basic sporting principles and numerous examples in cycling and elsewhere justifies such a policy," De Boer said.

"Anti-doping authorities are fighting a hard battle with true doping offenders.

"Unfortunately, as in every battle, there are innocent victims.

"Those victims also have rights and must have the possibility to prove their innocence and clear their names.

"In this specific case there are sound reasons to investigate the cause of this apparent doping offence.

"Such an investigation requires time and efforts from all parties involved, but I hope that André Cardoso will also get the opportunity to accomplish this examination.

"After all, it is my belief that innocent victims in the doping battle must be prevented at all costs."

Cardoso had been set to support two-time winner Alberto Contador at the 2017 Tour de France.

Contador said before the event he was surprised and disappointed in his team-mate.

Cardoso rode with Caja Rural before joining the WorldTour with Garmin-Sharp in 2014.

He left for Trek-Segafredo at the end of 2016.