McPherson tested positive for a prohibited stimulant named benzoylecgonine on June 29 at the USA Outdoor Track & Field Championships held in Sacramento.
"Benzoylecgonine is a metabolite of cocaine, a substance in the class of Stimulants prohibited under the USADA Protocol for Olympic and Paralympic Movement Testing and the International Association of Athletics Federations (“IAAF”) Anti-Doping Rules, both of which have adopted the World Anti-Doping Code and the World Anti-Doping Agency Prohibited List." the USADA wrote in its report.
"After a thorough review of the case, USADA determined a twenty-one month sanction was appropriate upon concluding that the athlete did not intend to impermissibly enhance her athletic performance through the use of a prohibited stimulant."
As a result McPherson's results dating from June 29 will be erased meaning that her personal best mark of 2.00m achieved in Sacramento is no valid.