All 44 athletes on the Jamaican team, including sprint superstar Usain Bolt, were tested on Monday in Russia at their training camp for the world athletics championships.
Team officials confirmed that agents from the World Anti-Doping Agency arrived at the camp in Moscow, where all of the athletes had blood taken in the sweeping operation.
It is not known if an entire national team has been asked before to undergo testing on the eve of a major competition.
The Jamaican track and field program has been under increased scrutiny over the past two months after former world 100m record holder Asafa Powell and his training partner Sherone Simpson were among five athletes who tested positive at the Jamaican championships in Kingston in June.
Powell and Simpson returned positive tests for the stimulant oxilofrine, results that came just weeks after two-time Olympic women's 200m champion Veronica Campbell Brown also returned a positive test at a meeting in May.
