Blood cells last up to 120 days, so blood transfusions should be readily detectable for 3 months or so. The second test just confirms the first, and really makes the B-sample analysis redundant.
It would be interesting to know if Vino had been properly tested earlier in the tour than the TT. I'd guess that the mechanics of processing tests on all 200 riders means that the pre-tour tests may be less thorough than later ones.