Papp served a two-year suspension from competitive cycling in 2006, after the International 42nd Presidential Cycling Tour of Turkey. His urine sample had tested positive for metabolites of testosterone or its precursors (6α-OH-androstenedione 6β-OH-androsterone), at a World Anti-Doping Agency-accredited lab in Ankara, Turkey. He was ineligible to compete in sanctioned cycling events from July 31, 2006 through July 31, 2008. Papp was "disqualified from all competitive results obtained on and subsequent to July 1, 2001," despite testing positive only in 2006, and after having signed an agreement with the United States Anti-Doping Agency (USADA) that negated only results obtained after May 6, 2006. After testifying in the Landis affair, in an interview with Dr. Dawn Richardson in VeloNews, Papp admitted to an extensive doping regime, including anabolic steroids and EPO. He recounted that, in his final race of the season for Team Whistle in Italy, what should have been a routine tumble resulting in bruising and road rash, instead almost cost him his life. The combination of EPO and blood thinners led to hospitalization with internal bleeding, and he admitted to having a hematocrit level of 58.