Blood Types: which are, rare type, who donates to whom?

For those who remember biology classes, blood types are classified by the ABO system, combining yet another analysis, which is that of the Rh factor. In general, the population is divided into types A, B, AB and O, whether positive or negative.

However, some people are born with rare blood types, even receiving a special name: golden blood. In such cases, they have a neutral Rh factor.

What may even seem interesting or special, is actually an added difficulty if the person needs a transfusion, as soon as it is quite difficult to find someone compatible.

Some research attempts to draw parallels between blood types and the most frequent diseases, indicating that there may be a greater occurrence of specific pathologies in each group. Do you want to know more about the groups that circulate in the veins of humanity? See in the text


What is blood type?

Blood type is the name given to the human blood group, which contains the most important blood types. They are: A, B, AB and O, which are subdivided into Rh positive (+) and Rh negative (-).

As early as 1600, people raised hypotheses and curiosities about blood transfusion. However, at that time, not much was known – in fact, almost nothing – about the fluid essential to life.

And for a long time, including several disastrous experiments that resulted in deaths, blood transfusion and blood types were mysteries for society. Only around the 1900s, a researcher named Karl Landsteiner took more significant steps to the understanding that we adopt today about blood types.

He found that certain blood samples agglutinated or dissolved their red blood cells (red blood cells) when they received a second blood sample via transfusion, while others did not.

In continuing his research, Karl noted that some red blood cells had certain antigens (substances that stimulate the production of antibodies) attached to their surface, which attract specific antibodies (defense cells) that are responsible for destroying them.

When he performed test transfusions, he discovered two types of antigens present on red blood cells, which results in two blood types. Landsteiner named them A and B.

In the case of unsuccessful transfusions, the blood types were not compatible, that is, the donated red blood cells had antibodies to fight the antigens that the individual contained in his body, leading the person to death in the same way.

There was also a third type of blood, in which the red blood cells did not carry any antigen, and the doctor gave the name “zero”, which ended up being known as type O due to its spelling.

Thus, each blood type carries antibodies against antigens of the other type, that is, antigens that the individual’s body does not have. So, if a type A person receives type A blood, they will not suffer any problems.

Otherwise, if that person receives a type B transfusion, their antibodies will fight against the B antigens, causing the blood to dissolve. When we talk about blood types, it is common to use the terms agglutinins to mention the antibodies and agglutinogens for the antigens.

Blood types and antigens

Although many people spend a good part of their lives (or even their whole lives) without knowing their blood type, this detail is essential if a blood donation or transfusion is necessary.

This is because each type has a unique characteristic and behavior, so that only some types can be mixed with others.

GroupABO antigenAntibodies you may haveAntibodies that cannot have
FROMA e BAnti-A e Anti-B
ONoneAnti-A e Anti-B

What is blood?

Blood is extremely important in the body, being responsible for several tasks, such as maintaining a constant body temperature, bringing oxygen to the cells of the body, bringing the carbon dioxide that we release during breathing, bringing nutrients to the cells and fighting diseases antibodies.

Normally, the human body has a blood volume of approximately 70 mL / kg of body weight for adults and 80mL / kg for children. The average adult has about 4,900 mL of blood.

Because it is extremely important in the body, its loss can result in death from hemorrhage.

In Brazil, the most used blood is O + (positive). Each blood bank must have a stock of at least 50% of that blood.

Blood determination: what is it?

Blood determination is immutable and occurs genetically, that is, what determines a person’s blood type is his or her genetic inheritance.

The transmission responsible for the blood type occurs by two alleles (segments of DNA): one is inherited from the father and the other from the mother, with the possibility of one of them being dominant and the other recessive.

For example: if the father’s alleles are AB (both uppercase because they are dominant) and mother Ab (with uppercase A because it is dominant and lowercase lowercase because it is recessive), we will have the following table for possible blood types of children of the couple.

Blood typesBb

Thus, children have a 25% chance of being blood type A (because A is predominant in b, as it is recessive), 25% of being AB and 50% of being type B.

Thus, an AB and Ab couple would never conceive a child with blood type O.

I don’t know my blood type, is this serious?

Who does not know the blood type need not despair. If a blood transfusion is necessary, it will only occur after the medical team has identified the compatible material.

If the situation is emergency, blood type O negative will be administered, since he is the universal donor.

What does positive and negative (Rh factor) mean?

In addition to the classification by the ABO system, there is also the Rh Factor, or Rh blood group.

Being positive means that the Rh antigen, also known as D antigen, is naturally present, while in the negative it is not.


Fator rhRh system antigen
PositiveAntigen D
NegativeWithout D antigen

The Rh factor is included in the Rh system, which is the most complex of the systems and the second most important blood group, behind only the ABO system.

The Rh system was discovered by the same doctor who discovered the ABO system in collaboration with Alex Wiener, also an Austrian physician.

This group system was discovered in 1937, through tests carried out on monkeys of the genus Rhesus. They observed that the serum of rabbits immunized with red blood cells from monkeys of the genus Rhesus agglutinated (gathered), forming small clusters.

Only in 1940, when associating fetal erythroblastosis – a disease in which the mother and baby have Rh incompatibility – with the research previously done, the researchers realized that Rh was a system.

Then, they released the result of the hemagglutination test, in which 85% of the different samples of human blood agglutinated when mixed with the serum containing anti-Rh.

However, it does not occur naturally for a human being to be born with Anti-D antibodies in their plasma, unless Rh + blood has previously been introduced into their body.

How can this introduction occur?

Inoculation (introduction) could occur through childbirth, an incompatible transfusion or the sharing of syringes in drug addicts.

Here is the concept that people with Rh positive blood can only receive Rh positive blood and the same is true with Rh negative blood carriers.

In reality, a Rh negative person can be exposed to Rh positive only once, without the risk of death, because at first he would be sensitized and would acquire Anti-D. From then on, the second transfusion could be fatal.

With medical advances, incompatible transfusions are unlikely to occur, so it is rare that this mistake is made deliberately. However, this is not the case in a pregnancy in which the mother and baby have incompatible Rh.

Blood compatibility: who can donate to whom?

Blood compatibility is essential so that, when there are donations or transfusions, the procedure does not involve risks to the lives of patients.

Check out what types can donate and receive to whom:

You can donate to:You can receive a donation from:
Blood type A +AB + e A +A+, A-
Blood type A-A +, A-, AB + e AB-A- and O-
Blood type B +B + e AB +B+,B-, O+ e O-
Blood type B-B +, B-, AB + e AB-B- e O-
Blood type AB +AB +A +, B +, O +, AB +, A-, B-, O- and AB- (all)
Blood type AB-AB + e AB-A-, B-, O- e AB-
Blood type O +A +, B +, O + e AB +O + and O-
Blood type O-A +, B +, O +, AB +, A-, B-, O- and AB- (all)O-

By donating blood, you are helping to save lives. In some states , blood donors have some benefits, such as:

  • Priority in medical care at SUS;
  • Priority in scheduling complementary laboratory tests by SUS;
  • Half admission to concerts, football games, cinema and cultural events;
  • Paid absence (once every 12 months employees have the right to miss work to donate blood).

Who can donate?

To donate blood, it takes a little more than goodwill. Know the basic requirements below:

  • Be in good health;
  • Be between 16 and 69 years old, since the last donation occurred until the age of 60 (for minors, additional documents are required.);
  • Weigh not minimum 50kg;
  • Have slept at least 6 hours in the last 24 hours;
  • Be properly fed (avoiding fats at least 4 hours before donation);
  • Present an original document with a recent photo (RG, work permit, driver’s license, liberal professional identity card or social security).

Who can’t donate?

Unfortunately, the group of those who cannot donate is much more extensive than those who can. Within it there are two subgroups. The definitive and the temporary ones, know them in detail:

Who cannot donate blood temporarily?

According to Hemobanco, they are temporarily prevented from donating blood:

  • People with colds and flu: if symptomatic and with fever, wait 15 days after symptom improvement;
  • People with allergies: only 7 days after the end of treatment;
  • People with diarrhea: only after 7 days of symptom improvement;
  • Pregnancy cases;
  • Women in the breastfeeding period (if the birth occurred less than 12 months);
  • Women 90 days after normal delivery and 180 days after cesarean delivery;
  • People who ingested alcoholic beverages in the 12 hours preceding the donation;
  • People who have had a tattoo in the last 6 months;
  • People who have pierced the oral and / or genital cavity prevent the donation for 12 months after its removal;
  • People with STIs (Sexually Transmitted Infections): only 12 months after healing;
  • People who went to endemic regions of Malaria: wait 12 months.

People who use drugs, undergo surgery, recently vaccinated, with hypertension, who use drugs, who have undergone dental procedures and cases involving other diseases should be evaluated by professionals.

Who can not donate blood definitively?

According to the Blood Center, those who:

  • You are under the age of 16 or over 70;
  • Have hypertension or hypotension at the time of donation;
  • You have a fever on the day of the donation;
  • Has an increase or decrease in heart rate at the time of donation;
  • Have anemia in the test performed before the donation;
  • You are being treated for hyperthyroidism;
  • Pregnant women or women who breastfeed babies under 12 months;
  • Who weighs less than 50 kg;
  • Who has risky sexual intercourse;
  • Have you used or used any illicit drugs in the past 12 months;
  • Who has heart problems (needs evaluation and declaration from your cardiologist);
  • Who has hyperthyroidism or Hashimoto’s thyroiditis;
  • Who did endoscopy less than six months ago;
  • Who has or has had a positive HIV test;
  • He had hepatitis after the age of 11;
  • He had malaria;
  • He has chagas disease;
  • Has infection with HBV (Hepatitis B), HCV (Hepatitis C), HIV AND HTLV I / II;
  • He received a duramater graft;
  • Had some type of cancer, including leukemia;
  • You have a blood clotting problem;
  • He has diabetes (type I and II insulin-dependent diabetes);
  • He already had elephantiasis;
  • You already had leprosy (leprosy);
  • You have had brucellosis;
  • You have severe heart, lung, kidney or liver problems;
  • He underwent total gastrectomy;
  • You have had extra-pulmonary tuberculosis;
  • He has had kala azar (visceral leishmaniasis);
  • He underwent pneumectomy;
  • Do you have a disease that creates legal non-accountability;
  • He underwent splenectomy not due to trauma;
  • He underwent an organ or bone marrow transplant;
  • You have autoimmune disease.

Plasma compatibility

Plasma compatibility is different from that of red blood cells (erythrocytes). With this, people can receive blood plasma from those who are not part of their group of compatible blood types.

Plasma transfusions are commonly performed to replace or assist the plasma that already exists in the body in the coagulation phase.

What happens with incompatible transfusions?

In incompatible ABO blood group transfusions, the Anti-A and Anti-B antibodies attack and destroy the transfused red blood cells almost immediately. The triggered symptoms usually start already during the transfusion. Are they:

  • Fever;
  • Chills;
  • Low back pain and possible brown urine.

This reaction is a medical emergency, which can progress to intravascular coagulation, that is, when blood coagulates within blood vessels.

In this case, professionals in readiness administer large amounts of saline intravenously, as this prevents the clotted red cells from obstructing the renal tubules.

It is not uncommon for people who experience this to develop some form of respiratory failure and / or hypotension .

Blood transfusions with incompatible Rh, on the other hand, are not usually so aggressive. The destruction of red blood cells appears 3 to 30 days after transfusion. The triggered symptoms are:

  • Anemia;
  • Fever;
  • Blood elevation of indirect bilirubin (bilirubin is a substance found in bile and which, when normalized, is expelled through the urine).

Rh antigen in pregnancy

Fetal erythroblastosis, also known as Rhesus disease, hemolytic disease due to Rh incompatibility or hemolytic disease of the newborn, can be diagnosed early in pregnancy.

During prenatal care, the obstetrician requests several tests, including the blood typing and the Rh factor of the mother and father, so it is possible to find out whether or not there are risks of incompatibility between the blood of the mother and the fetus.

The disease arises when a Rh- mother has a Rh + child for the second time. It only manifests itself in the second pregnancy, as the mother was only sensitized in the first.

The mother’s blood inevitably comes into contact with the blood of the fetus and, from there, begins to produce antibodies against the antigens present in the Rh + red blood cells, that is, the mother produces antibodies against the fetus.

It is important to mention that these reactions do not always happen and are even rarer when the fetus has antigens A or B and the mother does not.

As already mentioned, the organism does not produce antibodies to what is part of its DNA, they are only produced in rare situations like the one described above. So, Rh- people will never start the production of Rh +, because, having in their plasma an antibody opposite to their corresponding antigen, all their red blood cells would be destroyed by it.

If the woman is having her first child with incompatible Rh, it is necessary to have an injection of anti-Rh gamma globulin, also called anti-D, in the first 72 hours after delivery.

This prevents a second Rh + baby from having its red blood cells destroyed by the mother’s antibodies. This injection will destroy the baby’s cells that remained in the mother’s body before she is sensitized.

With that, we see the importance of prenatal care. After all, it is through him that it is possible to discover Rh’s incompatibility in advance.

Rare blood types (golden blood)?

Because it is compatible with any other blood type, O- blood is universal and, therefore, people associate it with the word “rare”. Another blood type that is considered to be rare is AB.

However, there are far more rare types than both described above. This is the case reported by the magazine Mosaic Science : the “golden blood”.

To understand how rare golden blood is, it is necessary to know that there are 35 blood systems, being organized according to the genes that carry the information to produce the antigens within each system.

Most of the 342 antigens in the ABO group belong to one of these systems. The Rh system alone has 31 antigens, being the largest of the systems. The most important antigen is anti-D, and when it is not naturally present in an individual, we call it Rh negative.

However, in golden blood, all antigens are absent. For this reason, it is called null blood. As of 2010, only 43 people were listed with this type worldwide.

Common blood type characteristics and diseases

Believing it or not, there are studies that claim that blood types reflect on the person’s personality. The best-known theory is that of Japanese professor Tokeji Furukawa, from 1930.

However, science has not yet been able to prove the veracity of this study. However, it can affirm the propensity for diseases of each blood type. Check out:

Type A carriers

The composition of a person’s antigens is what determines how much of a specific hormone it releases. In the case of this blood type, the release of cortisol is much greater, which makes it more prone to stress .

Type A is also 20% more likely to develop stomach cancer compared to types O and B, and a 5% higher risk for heart disease compared to type O.

Unfortunately, for people with this blood, the risk of getting pancreatic cancer, leukemia and infections like smallpox and severe malaria are higher. The good news is that A blood is less attractive to mosquitoes.

Type B carriers

People with type B have an 11% increase in the risk of heart disease. Women with B or AB blood are at an increased risk of developing ovarian cancer.

However, these people have up to 50,000 times the number of beneficial bacterial strains than people with type O.

Type AB carriers

These people have an increased risk of heart disease of 23% over type O.

AB women can suffer twice as many times from pre-eclampsia during pregnancy and both sexes have 82% more chances of having cognitive difficulties, especially in areas such as memory, language and attention recovery.

Type O carriers

Type O is more likely to have ulcers and rupture the Achilles tendons.

The good thing is that people with this blood have a lower risk of suffering from pancreatic cancer and a lower risk of dying from malaria than other blood groups. In terms of mosquitoes, they are twice as likely to repel them.

Blood type diet: does it work?

Incredible as it may seem, there is in fact a blood type-based diet. This theory was developed by the naturopathic doctor Peter d’Adamo and published in his book ” Eat right for your type ” which, translated, means” Eat correctly according to your type “. The book was published in 1996 in the United States.

According to Peter, for each blood type, foods are considered:

BeneficialFoods that prevent and cure diseases
HarmfulFoods that can aggravate disease
NeutralThey do not bring, nor cure diseases

According to the doctor, blood types have a strong influence on the body and determine the proper functioning of the metabolism, immune system, personality and emotions of each person. This interferes with well-being, weight loss and strengthens health, all from changing eating habits.

This diet shook the aesthetic and medical world, the controversy was so great that several researchers started their own studies on the blood type diet.

However, at the University of Toronto, Canada, a study of about 1,455 people found that an individual’s nutritional needs are unrelated to their blood type .

Ahmed El-Sohemy, the study’s coordinator, said that no evidence was found to support the doctor Peter d’Adamo’s theory, and that the way people react to the diets that Peter suggests are related to their ability to maintain a sensible diet. vegetarian or low in carbohydrates , not with your blood type.

Blood is fundamental in our organism, so it is necessary to be as well informed as possible about it. Therefore, the Healthy Minute brings more information about health and quality of life!