London, Aug 10 (IANS): British Anti-Doping (Ukad) chief executive Nicole Sapstead has warned that blood samples should be checked correctly before athletes are accused of doping.

Sapstead said all factors must be examined to ensure accuracy. The Times on Sunday published data from 5,000 athletes, which reveals an "extraordinary extent of cheating".

The newspaper reported that almost 30 percent of winners in the 24 men's and women's London marathon are suspected of cheating.

"You can't just look at anonymous data in isolation. You have to look at it in context," she was quoted as saying by bbc.co.uk on Monday.

"You have to look at whether that data was collected when an athlete was at altitude, after they competed, after they were training, whether they had a medical condition that might justify some of those results.

"This data, without a narrative behind it, can be misinterpreted. Let's say we have an athlete whose data shows a strange fluctuation at some point in their testing history. Then they have to go through the ordeal of explaining why there was a blip on their profile," he added.

Ukad commented on the doping allegations after a turbulent week that raised a big question on the integrity of athletics.

"It continues to draw speculation and inferences where there doesn't need to be any. I don't think any athlete should be put in the position where they feel the need to stop the public from suspecting them," Sapstead said.