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.
You can read full USADA report is here>>