Only one in 160 million people have it , that is, 43 worldwide. Known as Rh null, it was described in 1961 in an Australian aborigine and is due to a genetic alteration that causes antigens, which are used to classify blood groups, not to be expressed – blood has 61-.
Individuals with this characteristic share with those in group 0- a singularity: both are universal donors , but can only receive one transfusion from the same group. In the British town of Filton, the International Blood Groups Reference Laboratory (IBGRL) has a database with those of this small club to ensure that none of its members who need a donation are left without her. The initiative has a serious drawback: holders of Rh null reside in countries as distant from each other as Japan, Brazil, Ireland or the United States, which makes it difficult to move a bag if it is urgently needed. In the event that someone with Rh null has to undergo scheduled surgery, blood is previously drawn and stored – for 45 days – in case it is necessary.
As for the most normal groups, A, B, AB and 0, with their positive and negative variants, the most frequent in the world are A +, 0+ and B +, but the distribution varies greatly by country. For example, in Spain, 36% of the population is 0+, 34% A + and 8% B +. These proportions are similar in other European countries. On the other hand, the B + is very abundant in countries such as Saudi Arabia (33%), India (31%), Japan (20%) or Taiwan (24%). The 0-, universal donor, has a significant presence in Europe, where it ranges from 6% in France or Germany, 7% in Italy and 9% in Spain. On the other hand, in Asia it occurs very rarely (India, 2% or Japan, 0.15%).
