Yeah. It's not a soul thing (since they don't believe it souls) or an ownership thing, it's that you're taking blood into your body. Fractions and such are considered a grey area since it's not technically "blood" aymore.
I am a JW. Personally, I wont accept anything that I know of having been derived from blood. That would include the artificial blood mentioned here as it is so-derived (AFAIKT it has red blood cells and platelets).
But, already existing blood volumizers are normally sufficient to save a person who suffered extreme blood loss; restoration of flow is more important than restoration of all the blood contents.