Idea for how to use blood types

[Frank_Stein]

Both of those sound pretty OP to me. What about a person simply drawing their own blood and putting it back in to heal their damage.

Blood has a unique identifier for individual people. It's how the forensic scanners can tell the difference between whose blood is whose.

You simply check whether the blood they are receiving is theirs or another person's when getting a transfusion

Plus, unless medical starts without any blood, they'll have the easiest cure all. 

I think if having a blood type gives you a resistance to a damage type, you should be ineligible to receive that blood transfusion healing bonus

So getting the brute damage resistance blood type means you can only heal tox, burn, oxy, brain, and radiation damage from blood transfusions

I don't think it's anymore powerful than the purpose built medicines, the sleeper chambers, or cryotubes medbay already start with. Just give them a bag of each blood and then let them look for donors when they want refills.

Maybe your blood type damage resistance also only kicks into effect when your blood units are at a proper level.

Too low and you lose it, too high and it reverses into a weakness to a damage type.

You could probably also apply some chem stuff you need to do to the blood before it becomes suitable to use as medicine

As another bonus, this could factor into vampire stuff, as a vampire could heal specfic damage from eating specific blood types, or gain the damage resistance of the last blood type they ate