The warning follows the controversy surrounding Russian figure skater Kamila Valieva, who was at the centre of a doping scandal at Beijing 2022.

Valieva, who was 15 at the time of the Games, is not named directly in the report.

"While testing athletes in the lead up to a major event is important, so is ensuring that the laboratory has reported results," the report reads.

"As the ITA [International Testing Agency] reminded all winter Olympic IFs [International Federations] in their SSPs [Sport Specific Protocols], the IO Team would also like to remind all ADOs of the importance of ensuring that laboratories are well informed of the sample priority so that results, particularly AAFs [Adverse Analytical Findings], are reported with sufficient notice prior to an event in which the athlete is due to compete.

"A case in point is the extremely unfortunate situation of a figure skating athlete whose urine sample collected several weeks before the beginning of the Olympic Games returned an AAF.

"The result was reported after she participated in her first event.

"This is not the first time that a positive pre-Games test was reported during the Olympic Games as at least one athlete from the Tokyo Olympic Games received notification of a positive test during the Tokyo Olympic Games based on a pre-Games test.

"All athletes coming to the Games should be able to enjoy their experience and know that they are competing on a level playing field.

"This situation was not only challenging for the IF, NADO [National Anti-Doping Agency], IOC [International Olympic Committee] and ITA to manage but also, from an IO Team perspective, extremely sad to witness."

Among its recommendations, the IO Team suggested that "samples from athletes attending the Games should be prioritized by ADOs and quick turnaround times should be requested by ADOs from laboratories".

It added that a review of Anti-Doping Administration and Management System data should be "conducted by relevant Testing Authorities to ensure all analytical results have been received in a timely manner", and that WADA should "review this situation and determine, as the global regulator, what measures can be put in place to minimize, if not eliminate, such unfortunate situations for future events".

The report highlighted that the sample "was not collected during the Games, nor was it a sample that was part of the Beijing Games anti-doping program (sic)".

The IO Team was "kept informed", but "procedures were outside the scope of the IO Team’s mandate and observations under the applicable rules in place for the Beijing Games".

After helping the Russian Olympic Committee to team figure skating gold, it emerged that Valieva had returned a positive drugs test containing the banned substance trimetazidine in a sample provided on December 25 2021, although this was only reported by a WADA-accredited laboratory in Stockholm on February 8.

The team figure skating golds still has an asterisk alongside it, with the Russian Anti-Doping Agency (RUSADA) given until August 8 to investigate the case and reach a decision.

Valieva was only cleared to compete in the women's singles event by the Court of Arbitration for Sport (CAS), which opted against re-imposing a provisional suspension for a failed drug test.

Processing delays at the laboratory in Stockholm were blamed on staffing problems brought about by the COVID-19 pandemic, but the CAS Panel accused anti-doping authorities of a "failure to function effectively at a high level of performance and in a manner designed to protect the integrity of the operation of the Games".

During the Games, WADA said that the RUSADA had failed to flag Valieva's sample as a priority, and claimed that the CAS Panel had "decided not to apply the terms of the [World Anti-Doping] Code".

WADA's IO programme has ran since the Sydney 2000 Olympics.

The team for Beijing 2022 was chaired by Hitesh Patel, the rapporteur to the United Nations Educational, Scientific and Cultural Organization International Conference against Doping in Sport.

It was tasked with providing an independent review of all aspects of the anti-doping programme at the Games.

The report concluded that "the IO Team was impressed by the anti-doping program implemented for the Beijing Games and congratulated the IOC, the ITA, Beijing 2022, the Beijing Laboratory, the CAS and all other stakeholders who contributed to the success of the anti-doping program and to protecting the integrity of the Games".

Patel praised the collaboration between the various bodies.

"It was a privilege to lead WADA’s Independent Observer Team for the Olympic Winter Games in Beijing," he said.

"As the report highlights, the IO Team was impressed by the anti-doping programme implemented for the Games and congratulates the International Olympic Committee, the International Testing Agency, Beijing 2022, the Beijing Laboratory, the Court of Arbitration for Sport, the China Anti-Doping Agency and other key partners who contributed to this positive outcome.

"This involved hundreds of dedicated individuals from around the world that collaborated effectively before, during and after the Games to deliver a robust anti-doping programme and protect the integrity of the Games.

"In addition to highlighting the strengths of the programme, the report also identifies a number of recommendations for key stakeholders to consider for future Games.

"Above all, we must recognize the athletes who, despite the challenging circumstances presented by the global COVID-19 pandemic, played a central role in contributing to a successful Games."