Question: what kind of blood types are there? and how many are there?

Jean Bourke answered on 15 Nov 2012:

There are about 30 blood types due to over 600 sugars, proteins, glycoproteins (sugars+protein linked together), and glycolipids (sugar+fat linked together) possible. If you wanted to have your exact blood type there would be 30 factors!

The ABO type is the most important followed by the Rhesus factor. There are many other factors such as Kell, Lewis, Duffy, Kidd and MNS but there is less variation in these within countries and often they are not as important anyway.

Sometimes more than just ABO and Rhesus need to be taken into account. Luckily it is possible to test blood for all of these.

There’s quite a quick test that can be done to ensure that the blood being given to someone won’t be bad for them: you mix a bit of the patient’s blood with a bit of the donor’s blood and if they coagulate (go all lumpy) then they are not compatible.

It’s only a problem if the blood you are getting has a factor that you don’t, then your body can recognize it as foreign and attack. You can receive blood from someone who is missing one of your factors so long as they don’t have one you don’t. Your body won’t recognize the absence of something.