The Criterion for Blood Exiting the Body That Invalidates Fasting

Question: What is the criterion for blood exiting the body that invalidates fasting? And how does it invalidate the fast?

Answer: The blood that invalidates the fast is the blood that comes out through cupping, based on the saying of the Prophet (peace and blessings be upon him): And what is analogous to cupping in its meaning, which a person does by choice and causes a large amount of blood to come out that affects the body with weakness, also invalidates the fast like cupping; because the Islamic Shari'ah does not distinguish between two identical things, nor does it combine two different things.
As for what comes out of a person without intention, such as a nosebleed, or a wound to the body from a knife when cutting meat, or stepping on a glass, or something similar, it does not invalidate the fast even if a large amount of blood comes out. Likewise, if a small amount of blood comes out that does not have the effect of cupping, such as the blood taken for a test, it does not invalidate the fast either.