Blood Transfusion: From A Disbeliever to a Muslim?
Question :
Is it allowed to transfer blood from one person to another, and what if the two are of different religions?
Answer:
When a patient becomes so sick that the only way for him to get better is to undergo a blood transfusion, and when doctors are at least confident of the benefits that will result, he may be treated in this fashion, even if the donor and the recipient belong to different religions. Blood from a disbeliever, even though he may be at war with the Muslims, can be donated to a Muslim. And Muslim blood may be donated to a disbeliever who is not at war with the Muslims. May Allah send peace and blessings upon Muhammad, his family, and his Companions.
Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 8 Page 229