Clarifying - Armstong is not being accused of using drugs, but rather blood doping; the process of transfusing blood prior to an event, or use of a hormone that causes the body to produce more blood cells. There's no test for this as of now, aside from searching athletes' training areas for the necessary medical equipment.
Another point to ponder is artificial blood; if you need blood at a local hospital and they don't have your particular type, one option is to try artificial blood, which can work across many types. But this is only Artificial Blood 1.0 - if you can create it, then you can improve on it over time. This means the artificial blood of the future will be able to hold way more oxygen than standard old human blood cells. Runners doing multiple Ks at full sprint, swimmers doing lengthy races without ever raising their head out of the water, etc will all be possible, at speeds that are currently not. So will athletes who receive better blood simply no longer be able to compete? Will there need to be entirely new sporting leagues for the enhanced?