The ruling on the fasting of one from whom nosebleed or blood is drawn

Question: What is the ruling if blood comes out of a fasting person, such as a nosebleed or the like? And is it permissible for a fasting person to donate blood or have some of it drawn for testing?

Answer: Blood coming out of a fasting person, such as a nosebleed, irregular non-menstrual bleeding, or the like, does not invalidate the fast. Only menstruation, post-natal bleeding, and cupping invalidate the fast. There is no blame on the fasting person in having his blood tested when there is a need for it, and this does not invalidate the fast. As for donating blood, the safest course is to postpone it until after breaking the fast, because it is usually a large amount, and it resembles cupping. And success is from Allah.