♥♥♥ & Rhesus Blood Group Guide

A comprehensive guide on the beautifully realistic blood transfusion mechanic DayZ has in place.
What blood of which type to use on who and how.

Preparation

Many times throughout the game your group will find yourselves in dire need of blood. Unless your team is very well geared and constantly sated and regenerating blood, its not advisable that you harvest yourselves for blood for later use. Harvesting other players for blood is a much better option. Testing a player for their blood type with a "syringe" and "blood test kit" first before relinquishing your empty blood bags is a sensible course of action. Alternatively, testing yourself first may save you a lot of blood test kits especially if you find yourself being AB+ and so universally able to receive any type of blood. The best blood to extract, however, is of course the universal donor type O; usually Rh - being the absolute best option but Rh + great as well as I'll explain later.

Note: If you have disenfectant at hand don't hesitate to apply it to your IV kits etc. especially if they are of low item quality to help prevent any inadvertent effects. To keep with any apathy you have for your clients, theres no need to waste any disenfectant when harvesting other players for blood.

The Crux of the Guide

I will start with the ♥♥♥ blood system as it's the most important. Also be aware that upon respawn, your blood type changes.

• Type A can receive blood from A, O
  
  
• Type B can receive blood from B, O
  
  
• Type AB can receive blood from A, B, O, AB. Termed the universal recipient for a reason. You can use anyone's* blood.
  
  
• Type O can receive blood only from O! The Universal Donor; their blood can be used by anyone.

Note: Blood bags need to be combined with IV kits for transfusions to take place. Saline bags also provide blood although not nearly as much.

The Rhesus Factor

Most people will actually be Rh + and so ♥♥♥ is the only issue. Now, the only complication that arises from the Rhesus system is if you are of Rh - type and considering injecting Rh + blood of a compatible variety. So, in plain language:

• A Rh + phenotype can take both Rh + and Rh - blood.
  
  
• A Rh - person can take in Rh - blood only!

I also wanted to mention that in reality a Rh- person would be able to receive a single unit of Rh+ blood (of a compatible ♥♥♥ variety) in the most dire of situations. After that the person would be rhesus sensitized and unable to afford another Rh+ package. As far as I know this isn't yet in the game.

Summary

Here's a quick reference. The recipient is of course the receiver.

.

[Uncle]

I've played this game for years and I don't think a blood test has ever resulted with me being anything but O+

[Hreg Greffly]

im always O+ i think on private shard im AB+

[ReVengeance]

For some reason AB+ is supposed to be one of the rarest blood types in the game but over half of my characters have been AB+. luck perhaps. Or is a greater force at work here?

[Leafhit Puddingsbane]

im O+

[John Ultrakill]

I really hope I'm AB+.

[Santa]

"Overall HP in the game is governed by the amount of blood you have." - But that's wrong.

[Fives]

@Skinny Pete

I am very unlucky ._.

[genericwhitemale]

@ThreeFiveZoids
As O+, you can only receive O+ and O-.

[Fives]

So I am O+. I am having trouble what blood I can only take. I can only get O types, or I can get all postive types? Which one?

[esev]

Take your own blood and give it to yourself. Oh wait.