Published on
Updated
The O+ blood group concerns 36% of the French population, the O- group, 6%. What sets it apart from other groups? What blood can people with type O receive? Who can they donate blood to? Answers from Dr Syria Laperche, medical director of the French Blood Establishment (EFS).
What are the different types of blood groups?
A blood group is defined by a set of genetically determined antigens. In total, there are more than thirty blood groups with more than 350 antigens. The best known of these is the ABO system which was discovered in 1900 by the American biologist and physician Karl Landsteiner. This ABO system offers four possibilities of antigen expression : group A, group B, group AB and group O. “In the natural state, each individual has antibodies that correspond to the blood group that they do not have. In other words, people with blood group A have anti-B antibodies, people with group B have anti-A antibodies, people in group O, who are neither A nor B, have anti-A and anti-B antibodies, and people in group AB have neither of these antibodies. deciphers Syria Laperche, medical director of the EFS.
To this ABO system is added the Rhesus (Rh) system : we are either Rhesus positive or Rhesus negative. In Europe, 85% of people are Rh positive and 15% Rh negative. Combined with the ABO system, there is therefore eight possible combinations :
- Blood group A negative (A-);
- Blood group A positive (A+);
- Blood group B negative (B-);
- Blood group B positive (B+);
- AB negative blood group (AB-);
- AB positive blood group (AB+);
- Blood group O negative (O-);
- Blood group O positive (O+).
What is the difference between O positive and O negative? Is O- a universal donor?
O+ blood group compatibility: who to donate blood to?
O+ and O- people have the same blood group (O) but not the same rhesus (positive or negative). “The red blood cells of O+ subjects have the particularity of not being covered with any A or B antigen on their surface. O+ blood can therefore be transfused to subjects with blood groups A, B, AB or O. if they are Rhesus + (A+, B+, AB+, O+). People with blood group O have anti-A and anti-B antibodies. Therefore, people with group O can only receive blood from group O”, explains the specialist.
What are the benefits of blood type O-?
The red blood cells of O- people do not have any A or B or Rh antigens on their surface. It means that O- blood can be transfused to all subjects regardless of ABO blood group. This is why people in the O- group are considered universal donors. However, O- people can only receive O- blood.
Distribution: is blood group O rare or widespread in Europe?
In Europe, according to the French Blood Establishment (EFS), the O positive group concerns 36% of the population and the O negative group 6% of the population.
- A positive: 38% of the population;
- O positive: 36% of the population;
- B positive: 8% of the population;
- A negative: 7% of the population;
- O negative: 6% of the population;
- AB positive: 3% of the population;
- B negative: 1% of the population;
- AB negative: 1% of the population.
Positive or negative Rhesus group: how and why to know your blood group?
“Knowing your blood group is not obligatory. Determining your blood group is essential in case of need for transfusioneven if in certain emergency situations, protocols allow transfusing in complete safety if it is not known”, says Dr Syria Laperche. Bundling may have been carried out at birth (in which case it is entered in the health record), during planned surgical intervention or hemorrhagic situations.
“Moreover, grouping is systematically carried out in pregnant women at the start of pregnancy, especially to know the Rhesus, because if the mother is Rh- and the unborn child is Rh+, the mother can develop antibodies directed against the Rh of his baby The child's red blood cells are then destroyed which can lead to. endanger the baby's vital prognosis “informs Dr Syria Laperche.
If the test has not been carried out or the card has been lost, it is possible to request a blood test. The blood type can also be known when you donate blood.
Consequences of a transfusion with the wrong blood type
If a transfusion proves essential, a compatibility test will be carried out in advance in the laboratory to allow transfusion. The objective? Ensure that there is no blood incompatibility between the transfused person and the donor blood they will receive. Finally, a final safety check is carried out before the transfusion to check ABO compatibility between the transfused blood and the recipient group: the bedside test. “This step is essential because a transfusion with the wrong blood group exposes the patient to the possibility of hemolytic shock (destruction of red blood cells) or even death“, specifies the medical director of the EFS.
