(Reuters) - The World Anti-Doping Agency (WADA) is investigating UK Anti-Doping (UKAD) for allowing British Cycling to conduct its own probe after a sample provided by one of its riders contained traces of a banned anabolic steroid, British media reported.
A British rider's sample from an out-of-competition test in late 2010 was reported to have contained irregular levels of nandrolone.
Nandrolone is known as a "threshold substance", where the amount found in a sample needs to be above certain thresholds to trigger action by an anti-doping organisation.
Rather than UKAD undertaking the investigation itself as dictated by the WADA Code, the agency alerted British Cycling, which conducted its own internal investigation, the reports said.
WADA did not immediately respond to a Reuters request for comment. It said in a statement to the Mail on Sunday newspaper that it would contact UKAD for more details.
"Some of the information provided to WADA on this is of significant concern," a WADA spokesperson said.
"We have asked our independent Intelligence and Investigations Department to look into this matter and to contact UKAD to seek further information."
UKAD said it could not comment on individual test results but would be open to working with WADA if it required further information.
"Sometimes amounts of a 'threshold substance' can be reported by the laboratory in a negative sample which are found to be below the threshold where an investigation is required," a spokesperson told British media.
"These are trace amounts and can sometimes occur in the body naturally. The guidance from WADA is that these trace findings may be used to help to decide who gets tested and when in the future, but does not automatically lead to an investigation."
UKAD said later on Sunday it was working with WADA to investigate claims related to private testing carried out by British Cycling in 2011.
"UKAD is examining archives to confirm decisions that were taken in 2011 followed due process set by WADA," a spokesperson said in a statement.
(Reporting by Arvind Sriram and Rohith Nair in Bengaluru; Editing by Michael Perry and Ed Osmond)