Maha,
I have many times been transfused with hb 11. It is not dangerous but it is useless. The thing with transfusions is to receive only the necessary ones, not to burden yourself with one more transfusion than what is necessary. It is not clinically unacceptable though, you are not in any danger when in 11(for higher counts it is different), but it would be better to avoid any unnecessary transfusion.
Remember that a transfusion does not only mean good things--higher hb and so on. It also means higher iron load, infections, reactions - so it is advisable to avoid any unnecessary transfusions like I said.
Lena.