Tour de France winner Froome returns abnormal test result in Spain's Vuelta

Four-time Tour de France winner Chris Froome may have to forfeit his Vuelta title from earlier this year after an abnormal drug test result.

Chris Froome returned an abnormal drug test result when he won the Vuelta in Spain this year. (AAP)

British road cyclist Chris Froome returned an abnormal drug test result during his victory in this year's Spanish Vuelta, according to a joint investigation by the Guardian and Le Monde published Wednesday.

Froome's samples reportedly showed a high level of the asthma drug salbutamol in a test taken on September 20, according to the Guardian.

The four-time Tour de France winner is trying to challenge the finding, according to the British paper. If he is not successful, he could forfeit his Vuelta title.

Froome, who has asthma, said in a statement that his symptoms got worse during the Spanish road race and he upped his dosage, but claims that he stayed within the guidelines.

"As always, I took the greatest care to ensure that I did not use more than the permissible dose," he said, in a statement quoted by the Guardian.

The 32-year-old Briton made history in September when he became the first rider to win the Vuelta and Tour de France in the same year since Bernard Hinault did so in 1978.