Drug testing should be handled by the event staff that run these events.
Here’s what wiki says:
In October 1999, the USOC created the USADA to begin operation in October 2000. USADA’s status and alleged independence from the USOC contrasts the norm in the United States in which most professional sport organizations (MLB, NFL, NBA, NHL) manage the anti-doping aspects of their sports. As a result of USADA’s ongoing multi-year contracts with the USOC and the sport national governing bodies (USA Track & Field, USA Cycling, USA Swimming, US Soccer, etc.) the agency is responsible for managing the anti-doping programs including testing and results management for each sport’s athletes and events throughout the year. Despite its name and status as the country’s official anti doping organization, USADA is a private organization and not subject to government oversight.
Drug testing should be handled by the event staff that run these events.