The Watchtower Society's policy it continues to wickedly impose on it's members is completely unscriptural, period.
The whole point in scripture is because the blood represents the soul, the life of the creature that has been taken.
Every reference to prohibiting blood in scripture involves the death of a soul! This crucial contextual element is completely overlooked by the Society.
Blood transfusions do not involve the death of a soul whatsoever. They are in fact life-giving.
Not only that, the JW's stance is completely contrary to the principles Jesus clearly laid down that when it comes to fanatical adherence to the letter of the law, God wants mercy not sacrifice. Have they never read Jesus' illustration of the sheep stuck in the well, or the man with the withered hand cured, or the disciples plucking grain on the Sabbath?
Even in the Hebrew scriptures, Jehovah says human sacrifice is never something that he requires, which is effectively what the JW's blood policy demands.
Jesus Christ would never have used the symbol of drinking his blood if blood transfusions for saving lives was wrong in God's eyes.