What comes when you call upon a deity is generally only a small percentage of their energy or what I like to call a secretary. Only when you develop a strong personal bond with a deity do you begin to form a direct link.
If you are using the blood as an offering and not as a "trade" then I do not see a deity being angry over that. You are giving a gift of all that you have. It isn't like you can change it.
If it were used to gains something in return, if the deity is very "pure" itself, then it may have a problem with it. I would suggest saying something along the lines of "Accept this offering as a sacrifice of myself, and if this is not to your liking, consider the exchange forfeit." Basically, this is explaining that if they don't like it, you don't want anything from them. Sometimes spirits will do what you ask and consider your offering insufficient. Then they twist what they did for you so that it bites you as a lesson. They aren't all nice and it really really matters who you are dealing with. Some are really really pretentious!