Classification of blood groups: what are the types? Rhesus factor and what does it mean?

Blood test

What are the blood groups and the Rh factor, every person must know. And necessarily everyone should be aware of the type they belong to and their relatives, because sometimes there are emergency situations in which knowledge can save lives.

Information on these indicators may affect the choice of a sexual partner, since if there is a mismatch of rhesus, there is a risk of complications for the subsequent gestation of the child. So, what is blood, and what determines its subspecies in two systems: AB0 and Rh?

The group is inherited, but does not depend on race and gender


  • What is blood, and why is it divided into species?
  • Types of blood
  • 1 or 0
  • 2 or A
  • 3 or B
  • 4 or AB
  • What is the Rh factor?
  • Difficulties with rhesus
  • Why do you need to know your blood type?
  • How to read the result of the test for a blood group?

What is blood, and why is it divided into species?

Our body is a complex system that needs communication and coordination of its individual parts. For this, there is a kind of connective tissue - blood. It moves along a special scheme of veins and arteries with the help of a heart that pushes it from birth to the death of a person.

Performs such a liquid important tasks:

  • Transport, delivering the right substances, oxygen, hormones and other biologically significant elements that regulate the work of internal organs, removing the "waste" of vital activity of cells.
  • Regulating, maintaining a relatively uniform temperature throughout the body.
  • Protective, neutralizing infections and other dangers.
  • Homeostatic, maintaining a balance of chemical performance.
  • Nutritious, filling the organs with useful substances.
The circulatory fluid performs functions that support the life support of the body

Although the blood performs the same functions in any organism, it differs among different people. The name of the classification that orders the types of blood sounds like AB0. It implies four kinds of such a connecting fluid underneath, which differ due to the presence or absence of antigens and antibodies in them.

During life, the subtype of blood does not change, it is a constant. The group depends on heredity and is calculated on the basis of the results of the parents.

Classify the blood taken according to the ABO classification

What is the blood type of people, and what does each of them mean? We'll figure it out!

Types of blood

Separation of blood types is represented by the following table:

Latin number and letter Antibodies Antigens
I or 0 α, β no
II or A β A
III or B α AT
IV or AB no A, B

Both antigens and antibodies are protein compounds, the presence or absence of which determines the type of blood. The first are on the erythrocyte membrane, and the latter - in the plasma. At the same time, they interact with each other.

Varieties of blood fluid groups

Antigens are divided into two types: A and B, their combination creates a fourth blood group. The same picture with antibodies that "live" in the blood plasma. Their simultaneous presence creates the first group. For the two remaining combinations, either A and β (second), or B and α (third). When antibodies of different types occur, they react with antigens and form a precipitate. When the blood transfusion is not the same group, the agglutination reaction occurs. If this fluid is small, the situation is limited to anemia and jaundice. A large amount of foreign blood can lead to death.

What are the blood groups in humans, it is regulated by the ABO system, which takes into account all possible combinations of antibodies and antigens. To find out what type of person this person refers to, conduct a special test. A sample of blood is taken and mixed with the appropriate protein compounds and, depending on the amount and type of normal reaction and pathological, the result is determined.

1 or 0

Most of the people on the planet have the first blood type. This is due to the fact that it is more often manifested when a combination of different subtypes of the mother and father of the unborn child. If parents with 4 subtypes can conceive a baby with the same group with a probability of only 50%, then for 1 subtype this percentage increases immediately to 100.

Characteristics of people with group 1

Living with such a group is both difficult and simple - in the case of an emergency, it is easy to find such blood, but with limited resources, when there are only other subtypes, you can not do the transfusion. The first group is suitable only for the same blood.

The fact is that it does not have antigens and therefore is not dangerous to others, and 2 groups of antibodies perfectly cope with their task in someone else's blood. Of course, the best compatibility is provided by the "native" group, however, if necessary, the first can always help out.

2 or A

The second blood group is less common and contains opposite protein compounds of the same species. Its description is expressed in the following formula: antigen A is combined with antibody β. This type implies an immune response, that is, a conflict with a donor fluid in which another antigen is produced (B, AB-3 and 4).

Characteristics of group 2

Blood of groups 3 and 4 can not be transfused to patients with the second type in the ABO system, since they contain antigen B, which in turn requires the presence of antibody α. If it is not there, folding, death of red blood cells will occur, and a negative reaction for the whole organism will follow, up to a lethal outcome.

3 or B

This species is distributed in much the same way as the previous one. It depends on the percentage frequency of the appearance of a child with this group in parents with different blood types.

Classification of 3 groups

This blood works, as in the case of the second group, but it represents its complete opposite. This means that there is antigen B in it, combined with the antibody α. Since the second and fourth group (A and AB) contain the opposite antigen A, this means that such a transfusion will lead to serious consequences for human health.

4 or AB

Such a group is radically different from the first, more precisely, it represents its opposite. It, on the contrary, contains two antibodies to which there is no immune response, that is, the agglutination reaction when mixed with other types does not occur. Because of this, it is able to accept any donor without negative consequences.

Classification 4 groups

It is worth saying that the fourth blood is the rarest. Only a few percent of the world's population belongs to it. In this case, such a species with a negative Rh factor occurs three times less frequently than with a positive one. However, this is compensated by the possibility of transfusing blood with any other indicator and the corresponding rhesus.

Ideal compatibility is possible, of course, with an ideal match of the group, but with a fourth negative such a result is almost impossible to achieve. In serious operations, specially ordered portions of such blood are ordered in advance, which sometimes have to wait several long months.

Determining which blood groups are in a person according to the ABO system, it is worth switching to another division into two types - the Rhesus factor. This is no less important indicator for both blood transfusion and during childbearing.

What is the Rh factor?

The effectiveness of transfusion depends on the type of blood that a person has. The Rh factor is also taken into account before this procedure, so that no sensitization of the body occurs.

By itself, this indicator, Rh, means the presence or absence of a lipoprotein, which is located on the outer side of the erythrocyte membrane. There are only two of its states:

  • Rh +, which means the presence of such a protein;
  • Rh which implies his absence.

More than 85% of the world's population has a positive Rh factor. The remaining 15 have red blood cells without such protein, which means they belong to the rare species Rh-. What does this mean for a person, and how can it affect his life and health?

The main thing in blood transfusion, after determining the required group, is not to mix the opposite parameters of rhesus. It is vitally important for patients with Rh + to pour just such a liquid and vice versa.

This is justified by the fact that when there is a lipoprotein in the connective tissue, which should not be there (in Rh- people), the immune system "sees" it as the worst enemy and actively produces antibodies designed to to destroy. An aggressive protective reaction persists, and if a second error of the same nature occurs, the red blood cells are glued together.

Difficulties with rhesus

The body of a person with positive rhesus is in "greater safety" than in people with negative. Since Rh + is found, it is much easier to get in hospitals. If people with negative rhesus of the first group still have a lot, and to collect their donor fluid in the right amount is not is a special task in large medical centers, then with the same rhesus, only the fourth group - practically unreal.


Such blood is a rarity, so it happens that patients in an acute state, after a serious accident, are injured, due to a lack of a corresponding donor fluid.


Troubles due to rhesus threaten pregnant women. This happens if the mom and the child do not match the indicator. This can cause rejection, until the interruption of the child's bearing. Complications in this situation occur frequently, and in late pregnancy. Such women are much more often and longer on preservation and resort to artificial birth or cesarean section. However, in such a situation, a child with a disability may be more likely to be born.

Conflict involving such a protein compound is manifested only if the woman has a negative group and the child has a positive group. The immune system of the mother reacts to the lipoprotein, which is produced in the blood of the child and releases antibodies destined for its destruction. For a baby, this is dangerous, since its erythrocytes perish when killed. In all other cases, there can be no conflict, and the Rh factor of the father has no fundamental significance.

However, future mothers should not worry, because with due knowledge of doctors and the passage of regular examinations, this is successfully overcome. Modern medicine has a number of drugs that allow you to smooth out and balance the body of the mother and child and reduce risks to a minimum. The main thing is that a pregnant woman thinks less and is nervous about this.

During childbirth, a woman is given a special drug that suppresses the production of antibodies. This allows them to slow down their production in subsequent pregnancies. If this is not done, the number of second and third births will increase, which will further affect the child's body, its growth and the entire gestation process.

Why do you need to know your blood type?

All this is understandable, but why do you need to understand what groups are, and to which of them does your blood belong? In fact, it is very important, from the knowledge or ignorance of this factor, at times human life depends:

  • Blood transfusion is possible only if groups coincide. Before the scientists discovered that there were several types of this liquid, such operations ended in a lethal outcome due to the rejection of the transfused tissue.
  • The type of blood is found in newborns with hemolytic disease - when the mother and child group is incompatible, which leads to complications for the baby.
  • Before the surgical operation, the specificity of the blood is clarified in order to perform the transfusion if necessary.
  • The blood group and Rh factor are determined during pregnancy to track their compatibility with the mother and the baby and avoid danger to the baby.

Such information becomes very important in emergency cases: after accidents or mass cataclysms. Therefore, it is written in medical documents and even school diaries, it is advised to make special inserts in the passport or driver's license. This is necessary for the rapid response of doctors with a large loss of blood.

How to read the result of the test for a blood group?

In order to designate the blood subtype, the doctors in the analysis results indicate a Roman number that coincides with the selected group and the letter corresponding to it. In the end, the designation of the Rh factor is added. Direction itself is issued with the wording "blood test per group and Rh factor in the ABO system" (read as ab 0).

After we figured out what kind of blood groups are, what a Rh factor is, and what it means, we can say with certainty, that every person should necessarily know all these data about himself and his relatives in case of an emergency situation and urgent transfusion blood. These indicators are important for pregnant women or women preparing for it, if their rhesus is negative.

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