The World Anti-Doping Agency (WADA) has begun an investigation into a potential integrity issue with new generation security bottles used in doping control.
WADA said they had been informed by the accredited laboratory in Cologne, Germany, that security bottles introduced in September 2017 may potentially be susceptible to manual opening "upon freezing" of a sample.
The bottles are used to collect and store urine and/or blood samples when an athlete undergoes a doping control test.
"This situation, if confirmed, will raise concerns and questions," WADA said in a statement.
To compound the issue, bottle manufacturer Berlinger Special AG has told WADA they were unable to replicate the issue when the security bottles were handled per the product's instruction, WADA said.
Reuters was unable to immediately contact the manufacturer for comment.
Bottle security became a major concern when officials learned athletes' analytical results were manipulated and samples swapped at the 2014 Sochi Olympics.
Russia were banned from next month's Pyeongchang Winter Olympics after the International Olympic Committee (IOC) found evidence of an "unprecedented systematic manipulation" of the anti-doping system that has led to a series of suspensions.
Only those athletes cleared by the IOC will be allowed to compete in Pyeongchang as an "Olympic Athlete from Russia".
WADA said they were following up with the Cologne Laboratory and the manufacturer to further clarify the issue.
Two samples are taken during a doping test but generally the B sample is frozen and only analysed if the A sample has been found to contain a prohibited substance, WADA said.
