Mark Bosnich faces disciplinary action from Chelsea and the English FA after a B sample confirmed a positive test for cocaine.
Bosnich has been suspended since the first test returned a positive finding last month and the results of the second sample now open the way for the Chelsea goalkeeper to be charged by the FA.
The FA have refused to confirm the findings of the second test or comment about the case, but PA has learned that the result does show the presence of cocaine.
The test result means proceedings by the FA and Chelsea against Bosnich can now go ahead.
The 30-year-old Australian, who has only made a handful of appearances for Chelsea despite being paid around £40,000 a week, could have his contract with the London club terminated on the grounds of serious misconduct.
He has reportedly been suspended without pay since testing positive and recently checked into the Priory clinic in Roehampton for treatment for depression.
Bosnich's advisors had wanted the analysis of the B sample to be carried out in Moscow but it is understood it was sent to the Independent Olympic Committee-accredited laboratory in Paris instead.
The Australian international now faces a lengthy ban, though the FA can also order him to attend a course of rehabilitation and counselling.
Bosnich began his professional career with Manchester United but failed to make a first-team breakthrough and returned to Australia before signing for Aston Villa in 1992.
He stayed in the midlands but a series of run-ins with Villa boss John Gregory preceded his exit, and he rejoined Manchester United.
The signing of Fabien Barthez in May 2000 was the beginning of the end for him in his second spell at Old Trafford and his contract was terminated in January 2001.
He signed for Chelsea in the same month but has struggled to be much more than third-choice goalkeeper on a regular basis at Stamford Bridge.
PA