According to the method of handling blood prescribed by the Bible, blood when taken from a body was to be poured out on the ground as water and covered over with dust. (Lev. 17:13, 14; Deut. 12:16, 23, 24; 15:23; 1 Chron. 11:18, 19) Because God Himself said that life is in the blood and such shed blood is held sacred before Him, we should recognize that all life comes from and belongs to God. By ‘pouring it out’ on the altar or on the ground, we, in effect, are returning the life to God.
So, according to the scriptural admonition above, the practice of voluntarily donating blood simply to be stored for some future use appears to conflict with the method of handling blood prescribed by the Bible.
For more, see
God's View of Blood