Column: Are red spots in eggs dangerous? - The Straight Dope
What are the implications of blood spots on an egg’s kosher/pareve status, though? Kashrut laws are notoriously complicated and capricious in these matters.
““Blood” Spots: Far rarer than protein spots, these generally appear in the egg yolk. … If the blood spot is noticed after cooking, the individual egg with the spot should not be eaten. However, there is no problem with the utensils or with other eggs cooked in the pan.”
(However, I certainly defer to anyone posting here with more/better knowledge than myself, which is quite possible.)