It's exactly because I know what happened in Italy that I don't believe in blood doping.
In the years 1978-1985 the self transfusion was legal, and in Italy the Olympic Committee (CONI) gave officially the task to prof. Conconi to support with this system many athletes of endurance (also swimmers).
Every athlete could chose to follow, or not, the "advices" of Conconi.
Some athlete, like Alberto Cova (WCh 1983 and Olympic Champion 1984 in 10000m), Salvatore Antibo, the Selvaggio twins and Fontanella followed his system. Some other, as Francesco Panetta, Stefano Mei and Gelindo Bordin, refused.
During the era of self-transfusion, Antibo ran 27'39". When he stopped (in 1985) this practice, became the best European, running 27'16" and 13'05". Panetta won WCh 1987 (steeple) after the silver medal (10000m). Bordin won Olympics in Marathon.
In 1984, Italian swimming had one athlete for gold medal, Franceschi in 200m medley. He followed the Conconi system, and NEVER was able to approach again the same peformances.
In the self transfusion, there were personal parameters to know for understanding IF was possible to have advantages in the performance, or to have disadvantages riskig to finish the career.
If I have to give a percentage, during those years of "legal" practice, among the athletes who tried to use this manipulation, I say that no more than 40% had really advantages in their performances, and about 30% never were able to go back at the same level they had before the practice.
The period with the most wide use of EPO in athletics is probably between 1994 and 2001. During that period, the only parameter investigated was the level of Hct : if higher than 50, the atlete had to be suspended for 15 days, officially for "not risking his health".
From 2001, was possible to detect directly EPO in the urines, but still was possible to skip some test. Exactly for that reason, IAAF changed the rules, requiring, in case of some record, to have both the tests (blood and urine) for the homologation. Everybody remember the case of Brahim Boulami, positive after bettering the WR of steeple in 2002.
From that year, the most part of athletes (also of top level) quitted to use EPO (who used), but the general level of performances in 5000 and 10000m continued to grow.
This because the organisation of the race changed : when Bekele was in a race, normally he had to run fast, and every year tried to beat the WR of 5000 / 10000m one or two times. If you look at the lists of 10000m, you can see the best performances are all in races won by Bekele or Gebrselassie, because there was a pace very fast and even, and the best (but normal) athletes could take advantage from this situation.
I can't be sure about some WR : I can have my idea, but I can't know the particulars of training and management of those athletes (Morceli, El Guerrouj, Komen, Szabo).
But I'm sure about other WR : the steeple of Shaheen, the Marathon of Wilson Kipsang, the 800m of Rudisha (and before of Wilson Kipketer), the HM of Mary Keitany, for example.
This is, for me, the demonstration that is possible running at the top without any help, not only illegal, but also legal (Shaheen and Mary Keitany never took one supplement, also legal, for example).
And that's the reason because I continue to sustain a position that can make me appear as a fool, to some poster having in his mind the only idea of doping.
But of course I don't care about some stupid extremist only able to insult without saying anything true (also because doesn't know anything). How my grandmother teached me when I was 10 years old, "we need to take words from where they come", and, if come from an idiot "Minus Quam", can't disturb for the simple reason that don't exist.