Probably each and every one of us, at some point in our lives, whether it is a blood donation or a blood test extraction, has been exposed to this concept: blood group.

Knowing your blood group is extremely easy; you can ask for this service at a pharmacy where they offer it, or simply because you are a blood donor, you are sent a letter with this information a few days after the donation.

There are different blood groups; in this article we will discuss one of them in detail: blood group 0+ .

The discovery of this blood type

For centuries, the functions of blood have been a mystery. Although doctors sensed its great importance and tried to perform numerous blood transfusions in order to treat different diseases, in most cases this proved to be harmful to the patient, so this medical practice was forbidden for a long time.

It was in 1900 when the German pathologist Karl Landsteiner realized that the mixtures between which bloods were incompatible.

Thus, investigating further, he discovered the fact that on the surface of red blood cells can have two types of markers (antigens A and B) or no markers at all . He also discovered the antibodies present in the plasma, which react against these antigens on the surfaces of the red blood cells.

Blood type 0+

There are a total of 8 types of blood groups: A-, A+, B-, B+, AB-, AB+, 0- and finally, the blood group 0+ . Compatibility for giving blood depends on these letters and whether you are positive (+) or negative (-).

The blood group 0+ is known because can give all blood types (A, B, 0) that are Rh positive, but the blood group 0+ can only receive from 0+ or 0-. We will now look at what it means to be Rh positive, what these letters and number 0 imply, and why they are compatible or not.

Blood group types

As the pathologist Karl Landsteiner has already stated, the type of blood group is determined by the markers (marker proteins) or antigens that are present on the surface of the red blood cells. These antigens can be A, B, A and B together or simply not at all.

Like any antigen, it reacts with an antibody that tries to neutralize it . People can have antibodies in plasma against these antigens.

The presence or absence of antigens in plasma is a determining factor for compatibility when donating or receiving blood. Positivity (+) or negativity (-) also influences blood compatibility. Depending on these parameters, we have the following groups, as well as their characteristics

1. Group A

It is the blood group whose red blood cells have antigen A on their surface and in the plasma we find Anti-B antibodies .

2. Group B

It is the blood group whose red blood cells have the B antigen on their surface, and in the plasma we find Anti-A antibodies .

3. Group AB

This is the blood group whose red blood cells have the two antigens on their surface: A and B. In the plasma no antibody is found .

4. Group 0

Group 0 is the group where no antigens are found. However, plasma contains Anti-A and Anti-B antibodies .

Positive or negative?

The positive (+) or negative (-) accompanying blood type is defined by a factor in the body called factor D . Having it means being Rh positive and not Rh negative. This factor is present in the blood of 85% of people. The remaining 15% of the population is Rh negative and lacks this factor.

Both blood type and Rh positivity or non-Rh positivity will determine blood type. For example, a person with no red blood cell antigens will be blood type 0. If you also have plasma Anti-A and Anti-B antibodies, and are Rh positive, you will be blood type +. Therefore it will be type 0+ blood group.

Blood group compatibility 0+

As mentioned above, blood group 0+ can give any group: A, B or AB (as long as it is positive). This is because as there is no group with which anti-0 antigens are made, no one will react against it if blood is received from it .

On the other hand, the 0+ blood type can only be received from people with 0+ or 0- blood type, because people with 0+ blood type have anti-A and anti-B antibodies in their plasma and would react with everything other than 0.

Who can donate?

In practice, not everyone is fit to give blood . This depends on many factors, both physiological conditions and parameters, that is, the individual himself, as well as circumstantial parameters (exotic travel, contact with people infected with hepatitis, taking medication, pregnancy, earrings or recent tattoos, etc.).

As essential parameters, it is considered essential to weigh at least 50 kg to be able to give blood, be of age and feel in a good general state of health. On the other hand, you should avoid giving blood on an empty stomach and give blood in a minimum period of 2 months since your last donation .

In addition, since men have a volemia (total blood volume), they can have up to 4 times in the same year and women only 3 times.

Permanently, blood can never be given to patients with hepatitis B, Hepatitis C or HIV , insulin-dependent diabetic patients, epileptic patients (and under current treatment) or other serious diseases.

What about the blood that’s being drawn?

This blood obtained through blood donations, is used to treat illnesses with anemia, treatment of different types of cancer, treatment of accidents, bleeding, burns, organ transplants, surgical interventions, etc.

It is considered that 1 in 10 people admitted to a hospital will need blood and that 1 in 2 people resident in Spain will need blood at some time in their lives. Moreover, curiously, only 5% of potential donors donate blood a year, very little.

The blood, once it arrives at the transfusion centre, is divided into 3 components: red blood cells, plasma and platelets and transferred to people according to their needs .

Blood type is not a factor that is statistically equitably distributed in society. In Spain, the blood group that takes the lead is A+, with approximately 36% of the population, while AB- has only 0.5%.

The most curious group could be considered the 0-, since it is a universal donor (nobody makes antibodies against it and it does not have the factor D or Rh), but it can only receive from itself (since it has antibodies anti-A and Anti-B in plasma), and this sometimes causes supply problems in blood banks. So don’t hesitate, be generous and donate blood! You will save lives.

Bibliographic references:

  • Netter, F. (2019). Atlas of human anatomy. Elsevier Spain.
  • E. Hall, John (2016). Compendium of Medical Physiology. Studentconsult. Elsevier. 13th Edition.