This link here gives a bit of background about the test.
http://www.cyclingnews.com/road/2004...eatures/doping

I think they normally do 4 tests altogether Set A x2 and Set B x2 to try and make sure the tests results aren't a fluke. On occasions riders have failed their A test but then the B test has then shown them clear.

Apparently this type of blood transfusion, when you take out your own blood then put it in again later was first used at the Los Angeles Olympics when it was still legal, so I suppose it's not like you're taking a banned substance, just putting back your own blood, but all sounds a bit grim. Wouldn't fancy it myself.