There is a misconception that if you are ill and in need of a Blood Transfusion for a medical reason, you should refuse because it is against the wishes of God. It is not the truth, and we should read and understand the Bible and not spread false doctrine.
Looking through every Bible verse that deals with blood my understanding is the scripture speaks about eating blood, drinking blood, but nowhere does it say it cannot be, used for medical reasons.
The book of Hosea 4:6 My people are destroyed for lack of knowledge: because thou hast rejected wisdom, I will also reject thee, that thou shalt be no priest to me: seeing thou hast forgotten the law of thy God, I will also forget thy children.
Genesis 9:4 But flesh with the life thereof, which is the blood thereof, shall ye not eat.
Ezekiel 33:25-26 Wherefore say unto them, Thus saith the Lord God; Ye eat with the blood, and lift your eyes toward your idols, and shed blood: and shall ye possess the land? 26 Ye stand upon your sword, ye work abomination, and ye defile every one his neighbour’s wife: and shall ye own the property?
Leviticus 17:10 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.
Hebrews 4:12 For the word of God is quick, and powerful, and sharper than any two-edged sword, piercing even to the dividing asunder of soul and spirit, and the joints and marrow, and is a discerner of the thoughts and intents of the heart.