The Cycling Anti-Doping Foundation (CADF) announced there were no adverse analytical findings in the samples from 2013 to 2019 reanalysed as part of Operation Aderlass.
Following Operation Aderlass, which implicated athletes in skiing as well as cycling, the CADF was requested to reanalyse samples taken during the 2016 and 2017 seasons by the International Cycling Union (UCI).
Based on further information received from law-enforcement authorities and a comprehensive overall assessment, the CADF not only conducted the required reanalysis but also expanded the retesting to include samples as far back as 2013 and until 2019.
The CADF investigated more than 800 in- and out-of-competition blood and urine samples, with 50 per cent of the samples from 2016 and 2017.
This resulted in no adverse analytical findings being reported.
The reanalysed blood samples were also screened for, among a wide range of forbidden substances, haemoglobin-based oxygen carriers.
The results have been shared with the World Anti-Doping Agency and the Austrian authorities for review.
In addition, the reanalysed samples have been put in long-term storage for possible retesting should any new intelligence or further scientific developments emerge.
"With the challenges that this project presented in terms of scale and complexity, in the demanding context of the pandemic, it required a great deal of work by the CADF team, our group of highly skilled external experts, the WADA-accredited laboratories and the partners involved in the project," said CADF director Olivier Banuls.
"I want to thank each and every one of them for their dedication and professionalism as well as the cycling families’ continuous support in the fight to keep the sport of cycling clean.
"Finally, I would like to reiterate that these stored samples can be reanalysed again anytime if necessary."
Operation Aderlass was launched last year, with police raids conducted at the Nordic Ski World Championships in Seefeld in Austria and in the German city of Erfurt.
The raids followed revelations made by Austrian skier Johannes Dürr about blood doping in an ARD documentary.
A total of nine people were arrested and 16 searches were conducted, leading to an ongoing trial where sports doctor Mark Schmidt is among the defendants.
Prosecutors have accused Schmidt and his co-defendants of assisting athletes in blood doping since 2011, especially in cycling and winter sports.
Last month, Schmidt admitted that since 2012 he had been using doping methods and had given prohibited substances to athletes.
The defendants could face prison sentences of up to 10 years if found guilty, following anti-doping legislation introduced in Germany in 2015.