I really did not understand how the WTBTS donates blood machines in Europe, and yet I was told in the the USA that one could not even take their own blood.
The blood machines that were donated are to circulate and cleanse one's blood. Since the machine is viewed as an 'extension' of the body's circulatory system, JW's are allowed therapy that uses this machine.
It's different than autologous blood storage, where your blood is stored for future possible need. The JW's are not allowed to do that in either Europe or the USA.
The inconsistency comes in where the JW leadership allows use of other people's "blood fractions", which of course must be stored outside the body before they are transfused.