Maybe possible, but very unlikely. There are several parameters on a regular ole CBC that indicate a dimorphic population. It is very common to see in patients receiving blood transfusions. It is unlikely that a sample can be contaminated homogeneously enough to show these same results. As for Vino's excuse about the young versus old thing, there are a couple of blood test that can indicate that his bone marrow is trying to catch up for blood loss, I doubt that he came near to the loss required to put his body into this type of "panic" mode (like about 2 pints).
As for trying to cover for the presence of two blood types shows he may have bigger problems on the horizon. Meaning he didn't bother to get a compatible blood type, which could cause life-threatening conditions to occur.
Maybe even years down the road. What if he has to have a transfusion because of say a car accident? He has set himself up to a likely transfusion reaction, which could then take his life.
Do I feel sorry for Ras and the diary keeping of the pros? Not at all. It's part of the job. Don't like it...find another job. I think you should be fired if you don't follow the rules. Rabobank should have dumped him before the Tour started.