Cycling's world governing body the UCI has announced its intention to appeal against the decision of a Spanish court to destroy more than 200 blood bags seized during Operation Puerto.
Madrid judge Julia Santamaria ordered the destruction of 211 bags of blood and other evidence seized in police raids on Spanish doctor Eufemiano Fuentes in 2006, citing privacy laws.
Fuentes, a doctor specialising in sports medicine, last month received a suspended one-year jail term for providing blood-doping services to cyclists.
Fuentes confirmed in court he had clients from other sports, including tennis, football and athletics, but not that they had been involved in doping.
A statement from the UCI read: "The UCI can confirm that it will appeal the decision of the Madrid court of April 29 not to release to the UCI and other anti-doping organisations the more than 200 bags of blood and other evidence gathered in police raids in 2006, which were presented in the trial of Spanish doctor Eufemiano Fuentes."
Anti-doping agencies condemned the ruling while women's marathon world record holder Paula Radcliffe, an outspoken campaigner against doping in sport, said it was "vital" the blood bags were analysed to try to catch other cheats.
Radcliffe suggested the court's ruling could damage Madrid's bid for the 2020 Olympics.