Blood donation is a process by which a blood donor voluntarily has blood drawn for storage in a blood bank or for subsequent use in a blood transfusion.
Blood donations may be scheduled at local centres, or at times a "blood drive" will occur. These are events where a blood bank or other blood collecting organization will set up in a convenient location—such as a shopping centre, large employer, university, high school, or a local church—for people to stop in without appointment during their daily routine to donate blood. Sometimes a bloodmobile is used to run a blood drive. Usually a modified recreational vehicle, it is an easy place to run a blood drive because it is already set up for the process of blood donation.
Blood Group Basics
OK, folks, this post requires your full attention as it's all about the complicated differences between everybody's blood types. I've tried to make this as simple as possible.
Here we go.
- We all have these little marker things called antigens on the surface of our red blood cells.
- These are so tiny they can't even be seen under a microscope.
- Everyone's got different ones - blame your parents and grandparents for all that.
- In fact, only identical twins will ever possess all the same antigens.
- All that's very well and good, but when it comes to blood transfusions, there are two very important systems of antigens which need to be matched to avoid any nasty complications.
The ABO System
If you have blood group A then you've got A antigens covering your red cells.
Blood group B means you have B antigens, while group O has neither, and group AB has some of both.
The ABO system also contains lots of little antibodies in the plasma, antibodies being the body's natural defense against foreign antigens.
So blood group A has anti-B in their plasma, blood group B has anti-A (you probably get the picture at this stage).
To complicate matters though, group AB has none and group O has both of the antibodies.
Which means giving someone blood from the wrong ABO group could be fatal.
The anti-A antibodies in group B attack group A cells and vice versa.
Which is why group A blood must never be given to a group B person.
Group O negative is a different story.
The Rh system
Still with me???? !!!!!!!!!!!!!!!!
Well, it gets more complicated here on in, because there's another antigen to be considered - the Rh antigen.
Some of us have it, some of us don't.
If it is present, the blood is RhD positive, if not it's RhD negative.
So, for example, some people in group A will have it, and will therefore be classed as A+ (or A positive).
While the ones that don't, are A- (or, wait for it...A negative).
And so it goes for groups B, AB and O.
This effectively doubles the number of different blood types to be matched, because you shouldn't mix blood type A+ with blood type A-.
84% of the population is Rh positive.
(And yes, that means the other 16% of the population is running around with Rh negative blood.)
