An update on regulatory issues in antidoping programs in sport.

Doping control for national- and international-level athletes has undergone major changes in the past few years, and will continue to change at an accelerated rate. National antidoping organizations (NADOs) such as the United States Anti-Doping Agency (USADA) are being established by major nations to work with national governing bodies of sport. The World Anti-Doping Agency has been established to coordinate worldwide antidoping efforts with the NADOs and international federations of sport, and to implement a recently drafted World Anti-Doping code, which clarifies the definition of doping and establishes procedures to harmonize international efforts in sample collection process, testing laboratory accreditation, result reporting, and result adjudication. A number of substances and methods currently used in doping present serious challenges to the scientific community, and are described briefly. In addition, brief descriptions of other issues of significance to doping control, including the role of physicians in doping and the operation of the USADA, are presented.