[sansa's brows knit together in a tiny frown. she suspects anyone who calls somebody 'only' a warmblood could stand to lose a little more blood of their own.]

Warmblood is the best for blood transfusion, it's the universal donor. Just by giving blood you're doing more to help than most of the rest of us can. You might ask the healers if there's anything else you could do for them, though. We have a kitchen staff, but I've been helping to bring people a little food and drink before they have to stand up. And you mustn't forget to eat once you've given blood, either.