Russian discus thrower Darya Pishchalnikova is at risk for losing her Olympic silver medal after a positive doping test.

MOSCOW (AP) -- Russia's anti-doping agency says discus thrower Darya Pishchalnikova has been provisionally suspended by the IAAF after a positive doping test that could cost her the silver medal from the London Olympics.

RUSADA says the world governing body suspended Pishchalnikova dating to Oct. 31 until a final ruling in the case.

Pishchalnikova tested positive for the banned substance Oxandrolone in a reanalysis of a sample taken in an out-of-competition control last May. The original test was negative, but her sample was checked again months later based on a more advanced testing method introduced by the World Anti-Doping Agency.

The positive test means Pishchalnikova could be retroactively disqualified from the London Games, where she finished second behind Croatia's Sandra Perkovic.

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