Eating food that has blood in it, or quaffing blood as a drink, engages the person's digestive system. The nourishing elements in the blood are then absorbed into the person's own blood-stream via the whole digestive system, with the excrement showing a distinctive very dark, almost black colour. Carnivorous animals have black stools. That is what happens when blood is either eaten or drunk.
Receiving a whole blood transfusion engages the person's circulatory system directly, completely bypassing the digestive system. It is designed to keep the person from death if they have lost a large volume of blood (e.g. as in a dreadful traffic accident, or a catastrophic, sudden bleed after giving birth.) It is not designed to nourish the body, but to maintain a level of blood volume in the circulatory system that will stop the person having a heart attack for lack of sufficient volume. It is also designed to alleviate increasing, agonising pain due to cancer. That sort of thing.
Therefore, for the question to be raised, that God's directive against eating blood has to have more to it than "risk of receiving medical abnormalities" is a contradiction in terms, given what the Bible says about life being in the blood. Blood transfusions are all about saving lives. Further, the blood-donor does not lose his or her life in donating a pint or two of their own blood to save the life of another! God's directive about blood has nothing whatsoever to do with blood transfusions.
It is about the sacredness of God-given life, blood being a symbol for that. Thus, blood has to be treated with respect for God's gift of life. It is not to be treated as something mundane, like food or drink. But if it can be used to save lives (and hundreds of millions of lives have been saved due to medical use of blood or blood-products) then God be praised!
Blood transfusions are not a form of eating.