As the Tour moved into Pau, southern France, officials were waiting to see if the Kazakh star's 'B' sample also tests positive, meaning that Vinokourov would have injected red blood cells from a compatible donor to enhance his performance.
Marc Biver, Astana team manager, suspended Vinokourov on Tuesday, removed his team from the race, and went as far as to say his star rider was guilty until proven innocent.
Alexandre Vinokourov is just the latest cycling star involved in a doping scandal
Floyd Landis: Winner of the Tour de France in 2006. A victory that is not recognised by the race organisers following his positive drug test. Landis denies taking testosterone and is still hoping to overturn a US anti-doping agency ruling.
Jan Ulrich: The now-retired 1997 tour winner was forced out on the eve of last year's race after being implicated in Operation Puerto, a large Spanish investigation into a blood-doping scandal at a Madrid clinic that implicated more than 50 riders. He denies any wrongdoing.
Ivan Basso: Tour runner-up in 2005 he was also kicked out of last year's race. The Italian accepted a two-year doping penalty from his federation and says he "attempted" doping, but never went through with it.
Bjarne Riis: Became a national hero when he became the first dane to win the tour in 1996. Confessed earlier in the year that he had used drugs to win that race. Now a team manager, he declined to attend this year's Tour.
Richard Virenque: A seven-time winner of the King of the Mountains journey at the Tour. He was part of the Festina team kicked off the race in 1998 after police found large qualntities of doping material in a team car. "It became known as the Tour of shame".
Later at the team hotel, police searched garbage bags for any evidence of doping.
"We have to wait for the result of the 'B' sample. But for us, if his 'A' sample tested positive then he is guilty until the 'B' sample proves otherwise," Biver said.
Christian Prudhomme, Tour de France chief, was obviously upset by the news concerning Vinokourov, but the Frenchman said the sport will simply not tolerate cheats.
"I told the riders prior to the start of the race in London that this year was a chance for us to win them (the public) back," said Prudhomme.
"Well, we have missed that opportunity.
"But the cheats must understand that if they want to continue bringing scandal to this race, then they're playing Russian roulette."
Vinokourov's sample which tested positive for blood doping was taken after his victory in the 13th stage time trial of the race in Albi.
The 33-year-old was also tested after he won Monday's stage, although the result of that test is not yet known.
The official who informed Biver said the Kazakh's 'A' sample "contained an imbalance of young and old blood cells".
Vinokourov is not the first rider to have been caught by a homologous blood doping control, after American Tyler Hamilton and Spaniard Santi Perez were also found out by the WADA (World Anti Doping Agency) test.
Meanwhile, Danish rider Michael Rasmussen, the current leader of the Tour de France, is struggling to convince everyone that he is a drug-free competitor after effectively being told by the Danish Cycling Union (DCU) last week that he could no longer represent his country in the wake of revelations he has missed four random doping tests in 18 months.
The Rabobank team cyclist holds a 2 minutes and 23 seconds lead over Spanish rival Alberto Contador going into stage 16.
Both Rasmussen and Contador underwent random blood doping tests on Tuesday, but after a week of trying to deal with the speculation surrounding the race leader, organisers re-confirmed their belief that the Dane should not even have been allowed to race by his team.
Patrice Clerc, the president of the Tour de France's parent company, ASO (Amaury Sports Organisation), said Rabobank's failure to inform them of Rasmussen's missed tests was a "lack of respect
shown to the administrative rules"
Vinokourov is 'guilty until proven innocent',
said Astana manager Marc Biver, centre [EPA]
"We should have been told, we would have refused his participation because he is not a good role model for the others in the peloton," said Clerc.
Rasmussen, also 33-years-old, continues to claim his innocence, but it is clear that his presence, and especially in the hallowed yellow jersey, is not a welcome one.
Clerc admitted the great race had seen better days, but added that he would not let drug cheats bring the Tour down.
"I've never thought about ending the race prematurely. I repeat that we're involved in a war against doping, and in a war there are casualties," he said.
"The Tour de France is going through a dark period, but we're not going to lie down and let those who want to cheat walk all over us."