I don't see the controversy here.
They stated that the 4 main components are not to be transfused from one person to another. Ok, fine.
Except that this thing called plasma is not a component of blood, it is a substance that comes from the circulatory system that suspends the other components. It is 93% water. Water is water. Urine is 95% water. The difference between plasma and urine is just the levels of proteins, salts, minerals and other stuff.
As for storing it, in bible times they had no separation or refrigeration. When it was drained from the animal, if it was kept in a container, then it was dry out and rot. Now there is refrigeration to prevent that.
Those fractions are not red blood cells, white blood cells or platelets so they would not be prohibited to be given or taken from others.