Is the blood of legally edible animals pure or not?

Question 141 Is the blood of animals that are lawful to be eaten according to Islaamic law, such as sheep and cows, Najis (impure)?

Answer: All praise be to Allaah Alone, and peace and blessings be upon His Messenger, and his family and Companions. The Masfooh (spilled, poured forth) blood of slaughtered animals whose meat is lawful to be eaten like sheep and cows is Najis (impure); whereas, the blood remaining in the veins and meat of the slaughtered animal is Taahir (pure)… read more here.