Does a person’s blood type change throughout life and why? Can blood type change and why?

The division of blood into 4 groups according to the ABO system is associated with the presence of agglutinins in the blood - special antibodies that glue bacteria, viruses and other foreign objects together. Agglutinins are found in blood plasma, and erythrocytes contain substances that cause their formation - agglutinogens.

In humans, there are two types of agglutinins - α and β, and two types of agglutinogens - A and B. Their different combinations form groups: both agglutinins in the absence of agglutinogens - group I, A and β - II, B and α - III, both agglutinogens in the absence of agglutinins – IV.

Change of blood type

Blood type is an innate characteristic of the body. The production of the corresponding agglutinins and agglutinogens genes, which are located on the long arm of chromosome 9.

Like any genetically determined trait, blood type cannot change during life. However, sometimes you can meet people who claim that their blood type has changed. Pregnant women especially often talk about this. Of course, we cannot rule out cases of not entirely conscientious work by the laboratory technicians who performed the blood group test, but sometimes the cause of errors is changes occurring in the patient’s blood.

Causes of errors in analyzes

The blood test for the group is based on the fact that α agglutinin glues red blood cells containing agglutinogen A, and β glues B. The patient’s blood is sequentially mixed with serum containing α, β and both agglutinins and looked under a microscope to see whether red blood cells stick together or not, therefore The sign determines the presence or absence of certain agglutinogens.

In some diseases, the number of red blood cells also increases, while the number of agglutinogens decreases so much that the gluing of red blood cells containing them will not occur. In this case, the analysis will show blood group I, although in reality the patient has II, III or IV.

Some pathogenic microbes secrete enzymes that change the molecular composition of agglutinogens A, as a result of which they become similar to B, and then the analysis will show blood group III instead of II. After recovery, everything will return to normal. Distortions are also possible with blood cancer.

Thus, the blood type cannot change during life, but in some diseases and during pregnancy, conditions arise that make it difficult to establish the blood group and lead to errors in the analysis.

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Can blood type change?

The Rh factor is one of the most important characteristics of human blood, along with blood group. For example, the Rh factor is one of the parameters taken into account during blood transfusion.

Rh factor

The Rh factor is a parameter of a person’s blood, which actually represents the presence or absence of a special component in his blood - antigen D. If there is such an antigen in the blood of a particular individual, it is customary to say that he has a positive Rh factor or simply positive rhesus. Otherwise, he is said to have a negative Rh factor. Thus, in the world there are only two main variants of the Rh factor: there cannot be intermediate values in this sense.

A negative Rh factor is not a pathology: in such a situation a person can live normally and be absolutely healthy. However, a negative Rh factor is much less common compared to a positive one. According to doctors, about 15% of all people currently living on Earth have a negative Rh factor; accordingly, the remaining 85% are Rh positive.

Formation of Rh factor

The Rh factor is a trait that is inherited from parents to a child. Thus, it is an innate characteristic of a person and cannot change throughout life. In this regard, it is very important to know your Rh factor along with your blood type: this can be useful in case of life-threatening emergencies, for example, when an urgent blood transfusion is required. Once you remember this information, you won't have to worry about it becoming irrelevant.

If both the father and mother of a child are Rh positive, in most cases the child will also be Rh positive. A similar situation is associated with the negative Rh factor of both parents. Doctors consider the most difficult case to be the situation when the child’s parents have different Rh factors: for example, the mother’s is positive, and the father’s is negative.

The main difficulty in this situation is related to the possibility of a so-called Rh conflict, in which Rh

Can a person's blood type change? The clear answer is no, it is formed during embryonic development and is considered a constant indicator. The same applies to the Rh factor.

Despite this, some people claim that they have encountered a similar phenomenon in certain cases.

In this article we will figure out why these indicators do not change in a person throughout life and where such myths come from.

Blood type and Rh factor are genetically determined indicators that are formed in utero and are not age-related. They are passed from mother and father to child.

Information about the group, the production of the necessary agglutinins and agglutinogens is determined by genes that are located in the long arm of chromosome 9. Therefore, a priori, blood characteristics cannot change either due to age, or after transfusion, or in any other cases.

There is also a myth that there may be epigenetics - changing genes or having different DNA in different cells. Epigenetic effects could explain the change in the properties of red blood cells. But this has not been scientifically proven, so it is unrealistic to encounter this in life.

Most often, an alleged change in blood type occurs as a result of a diagnostic error during a previous or current analysis. During pregnancy and in the presence of certain diseases, conditions are created in the body that make it difficult to determine group membership and often lead to confusion and errors. In such cases, characteristics may change under the influence of hormones, viruses, toxins and the analysis will be inaccurate.

Brief information about existing groups and methods for defining them

Let's look at how the definition is generally carried out and why errors may occur.

Modern medicine uses the AB0 classification system, which distinguishes four blood groups and the Rh factor (Rh). Rhesus can be positive (Rh+) and negative (Rh-). If antigen D is present on the surface of red blood cells, it is designated Rhesus - plus, if absent - minus.

Blood consists of plasma and cellular elements - erythrocytes, leukocytes, platelets. Plasma contains agglutinins (α and β) - antibodies, and erythrocytes contain agglutinogens (A and B) - antigens. When antigens and antibodies of the same name interact, the process of hemagglutination occurs - the gluing of leukocytes. Based on this reaction, the group is determined and transfusion is carried out. If incompatible blood is transfused, a process of hemagglutination in the vessels is possible, which causes serious complications or death.

Blood classification according to the AB0 system:

I – called zero (0). In plasma it contains agglutinins α and β, but does not have antigens A and B;
II – designated A. It contains agglutinin β and agglutinogen A in the membrane of erythrocytes;
III – called B. It is characterized by the presence of antigen B and the content of antibody α in the plasma;
IV - designated AB, since it contains antigens A and B, but does not have antibodies α and β.

Blood group is determined in two ways: using standard sera and synthetic zoliclones. Serums are prepared at a transfusion station and sealed into ampoules. Zoliclones are special solutions that contain analogues of agglutinins α and β.

During the analysis, a drop of the blood being tested is mixed with serums or solutions, and the result is assessed within 5 minutes. Based on the appearance of hemagglutination (adhesion of red blood cells and the formation of grains), conclusions are drawn about the presence or absence of certain agglutinogens and group affiliation is determined.

Where do the myths about blood type changes throughout life come from?

In medical practice, it is mandatory to determine the properties and parameters of a person’s blood.

Most myths about group change are propagated by people who have experienced faulty analysis. Errors can occur due to many reasons, which we will discuss.

During pregnancy and after childbirth

During the period of bearing a baby, women undergo many hormonal, humoral and physiological changes in the body. The number of red blood cells increases significantly, and the number of agglutinogens, on the contrary, decreases. This may result in red blood cells not sticking together during analysis.

As a result, the study may show 1 group, when in fact the pregnant woman has 2, 3 or 4.

Based on this, we can conclude that pregnancy cannot change your blood type. Expectant mothers simply experience a change in the production of blood cells and substances that help determine the group. A few months after birth, the number of red blood cells will decrease and the analysis will again be reliable.

During blood transfusion

Sick people are always given blood transfusions only of the appropriate type.

But in extreme conditions or emergency cases, transfusion of group 1 (0) is possible, since it is universal and suitable for everyone. When conducting a study immediately after the procedure, the result may determine the blood group as 1. In fact, it itself does not change, only the analysis data changes.

During a bone marrow transplant

The hematopoietic organ is the bone marrow, which is located inside the bones.

Theoretically, the blood type can change if a person's bone marrow is destroyed and he needs a transplant, but the donor has a different group. Although in such cases, before transplantation, a donor with similar antigenic properties is usually selected.

In addition to blood parameters, the genotype of a man or woman must also be suitable. Indeed, if the antigenic profile of the donor and recipient does not match, an immune reaction and rejection of the transplanted organ may occur. Therefore, in practice, a change in group affiliation after a bone marrow transplant is still unlikely to be possible.

As a result of errors occurring during analysis

During any research, errors occur from time to time.

They are usually provoked by the following reasons:

incorrect conduct of the research procedure;
violation of blood sampling rules;
incompetence of employees;
non-compliance with the rules for setting up a reaction;
violation of the location of the reagents;
lack of control reaction;
use of low-quality serums;
incorrect ratio of blood and reagents;
failure to comply with transportation conditions;
storing samples at the wrong temperature;
unreliable interpretation of the result.

Sometimes you can come across such a concept as “floating” blood group and Rh factor. Such a term does not exist in official medicine. It was invented by people who, after conducting research, received different results each time. Variable results only indicate an error in the present or past analysis.

In addition, if the test is performed at the wrong temperature, the results may also change. Sometimes the blood tested contains cold agglutinins, which at temperatures below 15 degrees cause red blood cells to stick together. This process is called cold agglutination and produces an erroneous test result.

Due to difficult to determine blood type

A(II) and AB(IV) in erythrocytes contain antigen A, which can be of two types: A1 and A2.

Erythrocytes with A2 antigens are characterized by low agglutination properties compared to A1.

If estraagglutinins a1 and a2 are present in the blood, then during the analysis the serum with A2 and a1 agglutinates red blood cells with A1. This circumstance may lead to incorrect conclusions.

Blood chimerism

Blood chimerism is the presence in the body of red blood cells with a different genetic makeup, which differs in antigenic properties and blood group.

There are three types of this condition:

True chimerism. It occurs in heterozygous twins during fetal development, when there are two types of red blood cells in the fetal bloodstream. Immediately after birth, it is very difficult to analyze twins, because the body contains red blood cells with two different groups. A few months after birth, the twin’s red blood cells disappear, the child remains with his own cells and the analysis can be carried out without difficulty.
Transfusion chimerism. It is observed with repeated transfusion or transfusion of large volumes of red blood cells of group 1 (0) to people with group 2 (A) or 3 (B).
Erythrocyte chimerism. Appears after allogeneic bone marrow transplantation. The donor's red blood cells should completely replace them in the patient, but after the operation, partial chimerism is observed in the body - there are two types of cells (native and transplanted). Over time, complete donor chimerism occurs - all cells are replaced by donor ones.

Other reasons

In a number of diseases of the body, nonspecific agglutination of erythrocytes is observed, when erythrocytes can be agglutinated by any serum. This situation is observed in autoimmune hemolytic anemia, autoimmune diseases, hemolytic pathology of newborns. At the same time, it is impossible to conduct a study, since in all samples the sticking of red blood cells is observed.

In liver cirrhosis, extensive burns, and sepsis, increased agglutinability is observed. The cells under study stick together even in physiological solution.

With leukemia, cancer, thalassemia, reduced agglutinability occurs and analysis is also impossible. Diseases cause temporary changes that disappear after treatment.

Blood type refers to those genetic characteristics that are formed even before the birth of a child. It is considered a constant blood factor throughout life. However, some people are of the opinion that it is possible. Does a person's blood type change throughout life? To do this, you need to understand what kind of indicator this is and by what parameters it is classified.

A little about the main thing

Blood is an amazing biological substance. To designate it, medical practice uses two types of systems: the ABO system and the Rh system. According to the second system, people's blood differs depending on the presence of a special protein in the red blood cells. The blood factor can be positive or negative.

According to the ABO system, biological fluid is divided into groups according to the content of antibodies - agglutinins - in it. The main function of these substances is to connect molecules of foreign substances. Agglutinins are constantly present in plasma.

At the same time, red blood cells contain special substances that promote their appearance - agglutinogens.

There are two types of agglutinins - a and b. Agglutinogens are also divided into two types - A and B. The combination of different variants of the two types of substances can form the corresponding blood group:

In addition to these main groups, there are other varieties. But they are less common, so in medical practice there is more often a mention of 4 of them according to the ABO system and 2 according to the Rh factor system (positive - negative).

Special test

Blood type is determined by the adhesive ability of red blood cells. Based on this, you can understand whether it changes throughout life. After taking biological material, a special test is performed.

The essence of its implementation is as follows: special substances are applied to the diagnostic plate, which contain antibodies α, β, α and β. After this, biological fluid is dripped into each of them. The required serum to blood ratio is 10:1. After applying the material, the reaction taking place is observed under a microscope for several minutes.

Then, based on the observation results, the specialist determines the type of reaction:

no adhesion - group I;
the reaction was positive with sera that contained antibodies α and α+β - II;
adhesion occurred in serum containing antibodies β and α+β - III;
positive reactions were observed in all sera - IV.

Reasons for possible change

Having considered the features of the test, it is quite possible to answer the question: can the blood type change? This will become possible if antigens are no longer produced in red blood cells, or their production is weakened.

There are several factors that can provoke a situation where the blood type can change:

Factors	Description
Pregnancy	When carrying a child, the number of red blood cells produced increases. At the same time, the level of agglutinogens decreases. As a result, red blood cells do not unite. In this case, the blood group does not change. There is a change in the level of production of substances that help determine belonging to the appropriate type.
Errors during the test	Although the analysis is relatively simple, there is always the possibility of error. Therefore, blood type membership may change depending on life stage.
Development of certain diseases	A change in blood type can be triggered by infectious processes, the development of a tumor, or the occurrence of diseases that are accompanied by increased production of red cells. Various pathological processes in the body lead to an increase in the level of red blood cells. Those enzymes that are produced by pathogenic microflora can also affect the composition of agglutinogens.

In this case, the changing type is not due to the fact that a change in blood type has occurred, but to temporary phenomena. Upon recovery, or after effective therapy, the indicators will return to normal values. The occurrence of cancer processes also contributes to the fact that low levels of antigens or a weak reaction do not make it possible to determine the blood type and negative Rh factor during laboratory testing. In any case, it is impossible to answer the question of whether the blood type can change without special tests.

A little about the Rh factor

If there are situations where the blood type has changed, then a completely logical question arises: can the Rh factor indicator change? This factor, regardless of whether it is positive or negative, is inherited genetically.

A positive indicator is detected when the Rh antigen is present in the erythrocytes.

In order to answer the question whether the Rh factor pole can change, you need to understand the following. The presence of a special protein in red blood cells is established long before a person is born at the stage of intrauterine formation. These parameters cannot change during life. It is only possible that there are certain conditions that lead to the Rh factor changing polarity during laboratory tests (for example, if there is a positive one, a negative one is detected).

During a person's life, many parameters of his health and condition change. Blood type is an indicator that remains unchanged. After all, the combination of antigens formed during intrauterine development cannot change. If other blood data is revealed, this does not mean that it is changing. There was an influence of certain factors. Weakening of their action or disappearance will lead to normalization of blood counts. In addition, the possibility of error cannot be excluded, which is quite acceptable when conducting research due to the human factor - inexperience of the laboratory assistant or incorrect interpretation of the data obtained.

In contact with

Even from the biology course at school, we can tell what a blood type is. It represents a number of genetically inherited traits that cannot change in the natural environment. That's why, if you are wondering whether your blood type can change, then a positive answer is unlikely. It combines a set of molecules: red blood cells or agglutinogens of the ABO system. The latter are found both in red blood cells and on some cells of various types of tissues, and are even found in saliva or other body fluids.

In the first stages of intrauterine development, antigens of the AB0 system are already present, and by birth there are already many of them. The AB0 set cannot change even before birth.

With different quantitative combinations of antibodies and antigens, 4 groups are identified:

Group 0 (I) – the presence of agglutinogen H on erythrocytes, where it is an incompletely formed agglutinogen B or A. Plasma contains alpha and beta agglutinins.
Group A (II) – erythrocytes contain only agglutinogen A, plasma contains only agglutinin beta.
Group B (III) – erythrocytes contain only agglutinogen B, plasma contains only agglutinin alpha.
Group AB (IV) – A and B are present on red blood cells; agglutinins are not present in plasma.

In some cases, there may be errors in determining this characteristic of your blood. This is due to the possible weak form of A. Sometimes this leads to blood transfusion accidents. Sometimes, for a more accurate determination of weak A antigens, it is necessary to use special reagents.

Rh factor

For a more accurate determination, a person’s Rh factor is determined. This determination occurs thanks to the Rh antigen, which is also located on the surface of red blood cells. In medicine, there are 5 possible rhesus diseases. The main one is Rh (D), which allows you to determine whether a person has a positive or negative Rh factor. In the absence of this antigen, a negative Rh factor is determined; if detected, it is positive. This characteristic of your blood also cannot change throughout your life.

There are also less strong antigens in the Rh system. There are even cases of the formation of anti-Rh antibodies with a Rh-positive factor. These individuals have weak forms of D, also called Du. The percentage of this opportunity is small and amounts to about 1%. People who have it are required to receive a blood transfusion with an exclusively Rh negative factor, otherwise an Rh conflict may occur.

Donors with Du are considered Rh-positive, because even weak Rh (D) can also cause Rh-conflict in Rh-negative recipients. In case of Rh conflict, a patient with a negative Rh factor begins to produce antibodies against them, which can lead to the destruction of red blood cells.

When transfusing blood, it is necessary to strictly adhere to the group affiliation of the donor and the patient. To do this, before transfusion, it is necessary to accurately determine whether each of them belongs to one or another blood group. The best way to do this is to use a cross reaction. And this trend does not change over time.

However, in emergency situations, transfusion may be acceptable with some inconsistencies. Thus, red blood cells found in group 0 blood can be transfused into recipients with other groups. However, the use of whole blood is unacceptable. Red blood cells belonging to A can be transfused into patients with A or AB. Red blood cells belonging to B can be transfused to patients with B or AB. If a risk of Rh conflict is detected in a mother and child, it is necessary to take special measures, otherwise the child may be born with homolytic disease of the newborn.

So why is there an opinion that it is impossible to change your blood type under normal conditions?

When molecules of group antigens are formed, proteins are synthesized on the surface of red blood cells. The structure of a protein is determined from information taken from DNA. Each gene produces its own protein, which is part of a specific DNA fragment.

The ABO gene can imply 3 options for the development of events: A, B and 0. If a person has genes A and B at the same time, then AB (IV) will be determined. If any one gene A or B is present, A (II) or B (III) is determined accordingly. Group 0 (I) is determined if two 0 genes are inherited. It is determined at conception and does not change throughout life.

The Rh factor is determined by the presence of the D and d genes. Among them, D is dominant. Therefore, in situations of inheritance from one parent D, and from the second D, a positive Rh factor will be detected. Those. variants DD and Dd receive positive Rh and only dd – negative, and they will not change throughout life.

Options for the development of abnormal conditions

It happens that the determination of the blood group is not entirely accurate. Sometimes it may have some restrictions. There are cases when red blood cells A and B express themselves very weakly. Most often, this situation is observed in patients with leukemia or some other malignant diseases. Patients who have some kind of neoplasm or suffer from some kind of blood disease may have a decrease in the amount of natural antigens in the plasma.

It follows that in some people it is almost impossible to accurately determine this characteristic in a typical way. Those. it cannot change, but may be inaccurately defined. This is due to the difficulty of finding those same antigens on the surface of red blood cells. Their complete disappearance may indicate some kind of disease, including acute myeloid leukemia. However, the blood type itself does not change.

So why does the red blood cell show the absence of ABO system antigens?

Antigens such as A and B of the AB0 system contain carbohydrate molecules connected in chains. To carry out this process, the enzyme glycosyltransferases is required. In patients with acute myeloid leukemia, the activity of this enzyme changes and becomes lower. This is why antigens on the surface of red blood cells may not be detected.

With a large volume of lost blood, a patient’s life can often be saved only after a transfusion of blood and its components, in particular, red blood cells, which also has a group affiliation. In the vast majority of cases, single-group material is transfused. Of course, there can be no doubt that the blood type will remain the same.

However, in emergency cases, when the patient’s life is at risk and there is no time to wait for the right drug, doctors can try to transfuse the patient with blood of a different type. Thus, it is believed that group 1 is universal donors. On the surface of such red blood cells there are no proteins - agglutinogens, which can cause sticking and destruction of red blood cells. Therefore, when blood of any group enters, the introduced red blood cells will, of course, be attacked by agglutinins a and b contained in the plasma of people with group I (0). Some of the cells will be destroyed, but will perform their transport function, and will also saturate the body with iron, necessary for the production of new blood cells.

On the other hand, owners of blood group IV are considered universal recipients. On the surface of their red blood cells there are agglutinogens of both types - A and B. Blood of groups 1 - 3, entering the body of such a patient, will react by gluing agglutinins infused with plasma with the patient’s red blood cells, but this reaction will not have significant clinical significance .

The question arises: if a patient is transfused with the 1st blood group, will his own change? Or if a blood transfusion is given to a patient with group 4, will he still have it?

Blood type does not change during transfusion for several reasons:

this trait is inherited and determined by the gene set, which is not affected by transfused blood;
foreign red blood cells introduced into the patient’s body are quickly destroyed, and agglutinogens on their surface are utilized;
the amount of administered blood or red blood cells is always significantly less than the volume of the patient’s own circulating blood, therefore, even immediately after a blood transfusion, diluted donor material cannot affect the patient’s results.

There are four main exceptions to this rule:

initially or repeatedly when determining blood grouping;
the patient has a disease of the hematopoietic system, for example, aplastic anemia, and after treatment he may develop other antigenic properties of red blood cells, which were previously weakly expressed due to the disease;
a massive blood transfusion was performed, replacing a large volume of donor blood; in this case, for several days, until the injected red blood cells die, a different blood type can be determined;
the patient underwent a donor bone marrow transplant, before which all his own blood progenitor cells were destroyed by chemotherapy; after engraftment of the donor material, it can begin to produce cells with a different antigenic set; however, the likelihood of this is reduced to casuistry, since the donor is selected based on many parameters, including blood type. However, there are cases where after a bone marrow transplant, the blood type changes, as does the genetic structure of the blood cells. That is why the process of selecting a bone marrow donor with the closest antigenic characteristics is so important and so expensive.

You can calculate a child's blood type based on the blood types of his parents.