Blood

97. The blood of a human being, and of every animal whose blood gushes forth when its large vein is cut, is Najis. The blood of an animal like fish, or an insect like mosquito, is Pak because it does not gush forth.

98. If an animal whose meat is Halal to eat, is slaughtered in accordance with the method prescribed by Islamic Law (Shariah), and usual amount of blood flows out, the blood of which is still left in its body is Pak. However, the blood which goes back into the body of an animal due to breath taking, or because of its head having been at a higher level at the time of its slaughtering, is Najis. As per obligatory

precaution one should avoid himself from the blood present in the Haraam[1] part of an animal whose meat is Halal to eat.

99. As per obligatory precaution, one should refrain from eating an egg which has even the smallest amount of blood in it. However, if the blood is in the yolk (yellow potion) the albumen (white portion) will be Pak, as long as the skin over the yolk is not torn.

100. The blood which is sometimes seen while milking an animal, is Najis, and makes the milk Najis.

101. If the blood which comes from inside the gum of a tooth vanishes as it gets mixed with the saliva, the saliva is Pak, however, it is better not to swallow the saliva.

102. If the blood which dries under the nail or skin, on account of being hurt, if it is no longer called blood, it is Pak. But if it is still being called as blood, then it is Najis. If it can be removed easily, then it should be removed for Wudhu or Ghusl. But if it is difficult for a person to remove the blood in such case one should wash the injured part in a way that Najasat does not spread anymore and put a cloth or something like that on it, and wipe with the wet hand and as per precautionary measure one should also do Tayammum. 

103. If a person cannot discern whether it is dried blood under the skin, or that the flesh has turned that way because of being hit, it is Pak.

104. Even a small particle of blood falling in the food, while it is being boiled, will make the entire food together with its container Najis, and boiling, heat, or fire does not make it Pak.

105. When a wound is healing, and pus forms around it, that substance is Pak if it is not known to have been mixed with blood.

[1] Haraam part of an animal whose meat is Halaal are parts like testicles etc.