LAUSANNE, Switzerland -- Retests of all samples from swimming's world championships found no evidence of the recently detected steroid THG.

Swimming's international governing body did not say Wednesday how many samples it tested from the July competition in Barcelona, Spain.

THG, or tetrahydrogestrinone, was undetectable in standard lab tests until this summer.

The International Olympic Committee also plans to retest hundreds of samples for THG from last year's Salt Lake City Winter Olympics.

A final decision is expected this week at IOC executive board meetings in Lausanne.

British sprinter Dwain Chambers and four U.S. track and field athletes, including middle-distance runner Regina Jacobs and shot putter Kevin Toth, have tested positive for THG.