Perhaps you have a blood type that is hard to find, or one that can be donated to everyone. Perhaps you want to know exactly what it is that makes your blood unique, and prepare yourself for a future transfusion. Or perhaps you would just like to know more about the whole biological business surrounding blood. Whatever the reason, it is always good to know and understand your blood type, so we at BloodLink decided to break down the sometimes confusing information into bite size chunks just for you. Because we’re nice like that.
What determines your blood type?
Although your blood type is a biological phenomenon, culture can affect how you feel about the one you have. In some parts of the world, such as Korea and Japan, it is completely natural to know your blood type. They believe it affects personality and temperament and impacts (among other things) who you should be in a relationship with (like a horoscope, only less astrology, more biology). In other parts of the world, many people have no idea what their blood type is. This can cause some odd questions and raised eyebrows if you choose to take a jaunt across continents.
There are 8 major blood groups in the world and a few rare blood groups. Because your blood group is determined by your unique genetic makeup, the frequency of certain blood types varies globally. From the 8 major blood groups, the most common is O+ and the least common AB-. Rare blood types, on the other hand, are often only located in certain areas. The Bombay Blood Group, for example, was discovered in Bombay and is found mostly in South India.
Your blood type comes from your genetic makeup and is based on an intricate system of “antigens” that are present on your red blood cells. An antigene is a molecule on the surface of a red blood cell. Put simply, antigens are like the ID card of a red blood cell. Your immune system checks these ID cards to see whether a red blood cell is your own. If you receive a transfusion of blood that has a foreign ID card, it is seen as an intruder. Your immune system recognizes this foreign ID card and attacks the cells with “antibodies”. This causes “agglutination” – blood clotting – and can be fatal in some instances.
Which blood works for who?
If you are blood type A, and you accidentally receive blood type B, your body will recognize the B antigen on the red blood cells as foreign and release B antibodies. Similarly, if you are blood type B, and receive blood type A, your body will release A antibodies.
On the other hand, if you are blood type O, you have no A or B antigens on your blood cells. That means you can give your blood to almost anybody – there is no ID card to check, so you can pass by unnoticed! However, the immune system of people with blood group O will find any ID card problematic. So people in this blood group can only receive blood from other people with blood type O.
Finally, if you are a blood group AB you can take blood from A, B, AB and O! Lucky you! That’s because your body has a dual antigen identity and accepts almost all types of blood.
But what about the positives and the negatives?
Perhaps you’ve heard about the ABO system, but do you know what makes your blood positive or negative? Most people are unaware that this definition comes from something called the “Rh system”. They are also unaware that the name of this system comes from monkeys.
That’s right. Monkeys. Rhesus macaque monkeys, to be exact. And although they don’t look it, these monkeys are genetically very similar to humans – we share common ancestry from around 25 million years ago (it sounds like a lot, but compared to a rat, we’re basically second cousins). This makes these monkeys very useful for biological testing.
The “Rhesus factor” was identified by Karl Landsteiner, an important figure in blood science, who noticed that blood with the same ABO system still clotted on certain occasions when injected. He realized that there were other important antigens present that need to be taken into account.This Rh discovery had immediate practical importance because it explained a relatively common medical disorder known as erythroblastosis fetalis in pregnant women.
Unlike the antigens in the ABO system, Rh is not a single antigen. It is actually a set of around 50 antigens on blood cells that you either have or you don’t. If you do have them, you are positive. If you don’t have them, you are negative (not literally…this isn’t a glass half full/empty type thing). Positive blood types are more common, and people with a positive blood type can accept both positive and negative blood. People with a negative blood type can only take negative blood.
Confused? Our advice is if you don’t know your blood type or if you still find the whole thing a little overwhelming, one sure fire way to learn more is to go and donate! Find out whether your blood type is rare or common, whether you are a universal donor or receiver, and even how your blood type could affect your overall health. Plus, you have the potential to save the lives of people around you. Always a lovely thing to do.