Nothing is wrong with blood transfusions.
"Withhold not good from them to whom it is due, when it is in the power of thine hand to do it" Proverbs 3:27
What is wrong is if you eat it....cannibalism.
And whatsoever man there be of the house of Israel, or of the strangers that sojourn among you, that eateth any manner of blood; I will even set my face against that soul that eateth blood, and will cut him off from among his people" Leviticus 17:10
"...Bring me hither every man his ox, and every man his sheep, and slay them here, and eat; and sin not against the LORD in eating with the blood..." I Samuel 14:34
The medical team has to ensure that the blood for transfusion is safe from any impurities and that the blood type is compatible.
"For every creature of God is good, and nothing to be refused, if it be received with thanksgiving for it is sanctified by the word of God and prayer" I Tim. 4:4-5
"...I will ask you one thing; Is it lawful on the sabbath days to do good, or to do evil? to save life, or to destroy it?" Luke 6:9
Do you accept the truth from the Bible???