You probably know your blood type: A, B, AB or O. You may even know if you’re Rhesus positive or negative. But how about I tell you that in addition to those 2 systems (ABO and Rhesus), one could have as far as 28 other types in his blood? Intriguing, isn’t it?

28 in fact, until a week ago. The number has now grown to 30 with the discovery of 2 new blood types, raising the total, alongside the classics we know to 32 blood types discovered so far.

MNS, Lewis, Duffy, Kidd, Kell are the most known out of these systems. An A+ Duffy+ for instance, will face more restrictions if the donor wants to give blood and in this case the recipient must meet different criteria to be able to receive such blood, and not reject it nor have complications.

Those annex blood types are found mainly…