Both the UCI and Froome's team, Sky, issued statements on Wednesday morning confirming that Froome had a returned an adverse analytical finding (AAF) for asthma medication salbutamol from a urine sample taken after stage 18 of the race. Froome went on to win the race overall.
Should a sanction ultimately be imposed on Froome for the finding, his Vuelta win could be annulled.
Vuelta organsier Unipublic says that it has a position of "extreme caution" over the news, and that it hopes for the "issue to be resolved as quickly as possible".
"Regarding today’s news about Christopher Froome’s unfavourable test result during La Vuelta 2017, Unipublic, the organiser of La Vuelta, wishes to communicate that it will await the UCI’s official conclusion," said the Unipublic statement.
"The regulatory entity has launched an investigation and the position of La Vuelta’s organiser is one of extreme caution, as it hopes for this issue to be resolved as quickly as possible."
Froome's urine sample contained 2,000ng/ml of salbutamol, twice the amount permitted under World Anti-Doping Agency (WADA) rules.
Team Sky and Froome are currently gathering evidence to support their case.
A Sky statement read: "The notification of the test finding does not mean that any rule has been broken. The finding triggers requests from the UCI which are aimed at establishing what caused the elevated concentration of salbutamol and to ensure that no more than the permissible doses of salbutamol were inhaled.
"There is considerable evidence to show that there are significant and unpredictable variations in the way salbutamol is metabolised and excreted. As a result, the use of permissible dosages of salbutamol can sometimes result in elevated urinary concentrations, which require explanation.
"A wide range of factors can affect the concentrations, including the interaction of salbutamol with food or other medications, dehydration and the timing of salbutamol usage before the test."
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