IIRC there were two EPO tests devised early on, and it took several years for one to be adopted.
There are ways to see if autologous transfusions are used, they look at haematocrit levels and these days compare them to the riders 'biological passport' or baseline bloods.
In the past it was less cut and dried, the levels were tested and levels would either fall into a 'normal' range or 'suspect'.
Pretty sure Marco Pantani failed on this basis once ?
The riders that have implicated LA haven't all failed dope tests, only Floyd Landis, Tyler Hamilton and maybe Levi Leipheimer are convicted cheats (can't recall if Levii ever failed a control ?)
George Hincappie (LA's Lieutenant for many years) Dave Zabriskie (sp?) Matt White, etc never failed a doping control, but have come out and admitted they doped, damning LA in the process.

