I keep hearing on the news lately that O negative donors are in high demand (or is it O positive? one of the Os), because it is the “universal donor”. Well, with my lowly B- blood, should I even bother donating? Is my blood useful? I just have this image of my lonely pint of blood sitting unused in the blood bank until it is no longer usable, because the hospitals all want O negative blood instead.
What’s the deal?
(The question is moot right now because I’m pregnant and can’t donate blood anyway, but for future reference I’d like to know.)
Well, if I was a B-, I would certainly want an extra pint in the hospital fridge just in case I needed it.
O- is the universal donor. You as a B- would be able to use B- or O- only. By having an extra pint of B- in the fridge for someone else who is B-, that pint of O- can go to someone whose blood type is unknown or is in extreme duress.
Yes, you should still donate. O negative is the universal donor. If someone REALLY needed some blood and there was no time to type their blood, they would could hook them up with a pint of O negative. I am not a doctor (obviously) but I am sure they would prefer to give someone their actual type. O negative is a stop-gap measure to buy them some time. Therefore there is need for B negative as well.
All blood isn’t the same. It contains certain enzymes, which we’ve labeled A and B. Whether or not your blood has either or both these enzymes is heredetary and coded into your genetic structure. A person either produces enzyme A, and we say he has blood type A, enzyme B, and we say he has blood type B, both enzymes A and B, and we say he has blood type AB, or neither enzyme, and we say he has blood type O. Your blood also contains antibodies against enzymes it doesn’t create. For example, since you’re blood type B, you have antibodies against enzyme A. If it’s put in your bloodstream, your blood will coagulate and you could die. Any blood you donate, likewise, can only be safely used in people without B enzyme antibodies…either people with B blood or people with AB blood. As you can see, since O blood has no enzymes in it, anyone can receive it, and since AB blood has no antibodies against any enzymes, a person with AB blood can receive any blood type.
There’s another enzyme, that’s called “Rh”, because it was first found in Rhesus monkeys. You’re Rh negative, which means that your blood doesn’t contain this enzyme (and that you have antibodies against it).
Combining these two factors, we see that people with O- blood (having no enzymes) can give blood to anybody, which is why blood companies want it so badly…it’s the most versatile for them to have. This doesn’t mean that your B- blood can’t be used…it most certainly can, but just not on everyone.
Not directly realted to the OP, but has anyone ever looked in the Guiness Book of World Records? They have a category for “Rarest Blood Type” and they list something other than AB-…what’s up with that? Is there a few “mutant” types too small to really talk about?
B- blood can be used by (preferentially) other B- folks, or on B+, AB-, or AB+. Hospitals are bound to have a few folks of those types, and they’re bound to know in advance that a few of them are those types. They’ll use your blood.
Ok, thanks! Good to know. If it hadn’t been for that one quarter in college that I had a low iron count, I would have got the free T-shirt and pin for donating six consecutive quarters. I’d hate to think of all that blood going to waste.
Is there a better labelling system for blood types?
Maybe some mathematician out there can come up with a simple system with dirt simple rules?
For example, say each blood type was represented by an integer. If I am type 5, I can accept all blood types less than or equal to 5.
Simple to understand, easy to remember, and no rhesus monkeys flying about.
Heck, I’ll even allow a rule like accepting all odd-numbered blood types less than or equal to my own.
Feel free to post a conversion chart of your proposed system. I would imagine the chart and some examples are easier to do than several paragraphs of detailed explanations.
MsWhatsit, since you’re pregnant, make SURE you tell your doctor that you’re B-. There are certain complications that can arise if you’re B- and your baby is another blood type that can be very easily prevented if your doctor is aware of your blood type. I’m sure she/he already is, but I thought it was worth a mention.
I’m sorry I can’t give you better details…I vaguely know what the complications are, but not well enough to expound.
(I’m B- too!)
I don’t know what blood type the Guinness Book lists but I do know of one odd type. There is an extremely rare variant of the O blood type referred to as Bombay O. These people can only accept blood transfusions from other Bombay O. There is a family hereabouts with a few members who have this blood type. The local blood center keeps some of their donated units frozen in case they need them in the future.
Possibly boring explanation of what the Bombay O type is goes like this:
All red blood cells, regardless of ABO type have some molecules sticking out of their membranes called H substance. The glycoproteins that determine what your blood type is are stuck on top of this H substance. Now your immune system generally won’t make antibodies to an antigen that you have. This means that type A people have anti-B in their blood but not anti-A. Type B people have anti-A in their blood but not anti-B. Type AB people have neither anti-A or anti-B in their blood and type O people (think of the O as being a zero) have both anti-A and anti-B in their blood.
Now through some genetic quirk, Bombay O type red cells lack any of the H substance so these people produce anti-H. Since H substance exists on the cells of any blood type other than Bombay O transfusing any blood of these types leads to the anti-H attacking the red cells. Much cellular destruction and mayhem ensues and presto, hemolytic transfusion reaction. Very nasty.
You’ve got your A enzyme. You’ve got your B enzyme.
You can have one, the other, both, or none. If you’ve got an enzyme, you can only accept blood from donors with that enzyme. If you DON’T have an enzyme, you CAN’T get blood from a person with that enzyme.
Then you just add on your RH enzyme, and follow the same rules.
It can’t work that way. Someone A+ can take A blood but not B. Someone B+ can take B blood but not A. If we were to call A+ “3” and B+ “4”, then someone with type-4 blood couldn’t take type-3 blood. But if we switched the names, then the new type-4 person couldn’t take new type-3 blood either. Although us lucky AB’s can take both A and B, most people can take only one of those.
–Cliffy
P.S. My blood donor card says I’m a “CMV Hero.” When I asked my phlebotomist what that meant, she seemed to indicate it was yet another blood factor (separate from the A/B and the rh factors), but her explanation wasn’t particularly in-depth. (As she was trying desparately to reassure me that everything was all right. That’s the general reaction I get whenever I ask a phlebotomist anything because that’s what drives most of the questions that other people ask them.) Anyone know what this is?
CMV refers to cytomegalovirus, not a blood factor. Most people become infected with it at some time in their lives and it’s usually pretty innocuous, many will never even realize they have it. However it can be dangerous for people with suppressed immune systems such as bone marrow or solid organ transplant patients. If such a patient has themselves never been infected with CMV their doctors would only give them CMV negative blood.
I also meant to mention last time that blood group factors such as A and B aren’t really enzymes, they’re antigens attached to the red cell membrane.
Oh, and I’m a Blood Banker. Forgot that too. Sorry to be so fragmented.
I have B- blood and during one hospital stay when I needed a transfusion, they had none. They say it is more rare than others. So by all means, donate (when you can) I am.
The system is simple. You can’t receive anything you don’t already have. An AB+ has A, so they can accept A blood, they have B, so they can accept B blood, and they have Rhesus, so they can accept Rhesus blood. In other words, they can take anything: AB+ is the universal recipient. A person with A+ can accept A and/or Rhesus, but they can’t accept anything with B in it, so B and AB are out of the picture. A person with O- doesn’t have A, B, or Rhesus, and thus can only accept other O- blood. On the other hand, since O doesn’t have any of those potentially troublesome proteins, anyone can safely receive it: O- is the universal donor.
Ideally, you want to get blood of your exact type, and you can cut a little more slack with the Rhesus factor than you can with A or B, but that’s the gist of it.
I vaguley recall reading an article about an machine in development that could strip the enzymes from blood cells, turning any type of blood pumped through it into O. Sounds like somehting that could really make a difference.