Blood types refer to the different types of blood that can be found in the human body, and are determined by the presence or absence of certain antigens (markers) on the surface of red blood cells. The most important blood groups for human blood transfusion are ABO and Rh.
The ABO blood group system is based on the presence of two antigens, A and B, and their corresponding antibodies, anti-A, and anti-B, in the plasma. There are four ABO blood types:
Type A: has the A antigen on the red blood cells and the B antibody in the plasma
Type B: has the B antigen on the red blood cells and the A antibody in the plasma
Type AB: has both A and B antigens on the red blood cells and no A or B antibodies in the plasma
Type O: has no A or B antigens on the red blood cells, but has both A and B antibodies in the plasma
In addition to the ABO blood types, there is also an Rh factor, which is determined by the presence or absence of a protein called the D antigen on the surface of red blood cells. If the D antigen is present, the blood is Rh positive; if it is absent, the blood is Rh negative.

Rh-positive blood: Rh factor is present in the red blood cells, and 85% of people are Rh-positive
Rh-negative blood: Rh factor is not present in the red blood cells, and 15% of people are Rh-negative.
Who discovers the blood group?
Karl Landsteiner, an Austrian physician, discovered the ABO blood group system in 1900. He discovered that blood from some individuals clumped (agglutinated) when mixed with blood from other individuals, but not when mixed with blood from certain other individuals. Through his research, he was able to identify the presence of different antigens on the surface of red blood cells, which led to the discovery of blood types A, B, AB, and O.
In 1902, another Austrian physician, Ludwik Hirszfeld, independently confirmed Landsteiner’s findings, and together they published their discovery in the same year.
In the following years, Landsteiner and his colleagues expanded on their discovery and identified other blood groups, including the Rhesus (Rh) blood group system, which was discovered by Alexander Wiener, Karl Landsteiner, and Philip Levine in 1940.
Karl Landsteiner was awarded the Nobel Prize in 1930 for his discovery of the blood groups, which is considered a major breakthrough in the field of transfusion medicine and has saved countless lives.
Which are the most common blood types?
The most common blood type is O+, which is present in about 38% of the population. This blood type is compatible with other O+ blood as well as O-, A-, B-, and AB- blood types.
The second most common blood type is A+, which is present in about 32% of the population. This blood type is compatible with other A+ blood as well as A-, O-, and AB- blood types.
The third most common blood type is B+, which is present in about 9% of the population. This blood type is compatible with other B+ blood as well as B-, O-, and AB- blood types.
The fourth most common blood type is AB+, which is present in about 3% of the population. This blood type is compatible with all other blood types.
It’s important to note that these percentages may vary depending on the population being studied and the location.
Rarest blood type
The rarest blood type is AB-. It is present in only about 0.6% of the population.
Which one is known as the golden blood type?
“Golden blood” is a term that has been used to describe a rare blood type called Rh-null. Rh-null is considered the rarest blood type because it is missing all of the Rh antigens (Rh-negative) and is compatible with only a small number of people. It is also referred to as the “universal donor” because individuals with Rh-null blood can donate to anyone, regardless of their blood type. However, individuals with Rh-null blood can only receive blood from another person with Rh-null blood.

The term “golden blood” is used because of the scarcity of this blood type and its ability to be used as a universal donor. It is important to note that while Rh-null blood is considered very rare, it is still a small percentage of the population and the term “golden blood” is not an official medical term.
Importance of blood grouping
Blood grouping is important for several reasons:
Transfusions: Knowing a person’s blood type is crucial when giving blood transfusions, as giving a person the wrong blood type can cause serious reactions, including death.
Medical treatments: Certain medical treatments, such as chemotherapy and kidney dialysis, can cause the destruction of red blood cells, making blood transfusions necessary.
Pregnancy: During pregnancy, a mother’s Rh-negative blood can attack her Rh-positive fetus, leading to a condition called hemolytic disease in the newborn. This can be prevented by administering Rh immune globulin to the mother.

Organ and tissue transplants: Blood typing is used to match donors and recipients for organ and tissue transplants to decrease the risk of rejection.
Medical research: Knowledge of blood groups helps in understanding the genetic and evolutionary history of different populations.
Forensic Science: Blood typing can be used in forensic science to identify suspects or victims in a crime.
Hence, blood grouping is an important diagnostic tool in medicine and plays a critical role in ensuring the safety and success of blood transfusions, organ transplants, and other medical procedures.
Blood types during pregnancy.
During pregnancy, it’s important to know the blood type of both the mother and the baby, as certain blood type combinations can lead to complications. The most significant concern is when the mother is Rh-negative and the baby is Rh-positive, which can cause a condition called hemolytic disease of the newborn (HDN).
In this condition, the mother’s immune system can produce antibodies against the Rh-positive blood cells of the baby, leading to the destruction of red blood cells and anemia in the baby. Symptoms of HDN can range from mild to severe, and in severe cases, it can lead to brain damage or death.
To prevent HDN, a mother who is Rh-negative will typically receive a shot of Rh immune globulin during pregnancy and after delivery to prevent the production of Rh antibodies. This shot can also be given after a miscarriage or abortion.
It’s also important to note that if the mother has a blood type that is incompatible with the baby’s blood type, it can lead to a condition called erythroblastosis fetalis, which can cause anemia and jaundice in the baby.
Hence, it’s important for the mother and baby’s blood type to be tested early in pregnancy so that if necessary, the appropriate precautions can be taken to protect the health of the baby.
These things should be taken care of during blood transfusion
Blood type compatibility: The most important thing to know is that the blood being transfused must be compatible with the patient’s blood type. ABO and Rh blood types must match between the donor and the patient to avoid serious reactions.
Screening tests: Blood is screened for various infectious diseases such as HIV, hepatitis B and C, syphilis, and others before it is given to a patient.
Reactions: While rare, transfusion reactions can occur. Symptoms can include fever, chills, and hives. If a reaction occurs, the transfusion should be stopped immediately and the patient should be closely monitored.
Blood storage: Blood should be stored at the appropriate temperature and used within a certain time frame to ensure its safety and effectiveness.
Blood donation: Blood transfusions rely on the generosity of donors, so it’s important to remember the importance of giving blood and supporting blood donation programs.

Monitoring: The patients should be closely monitored during and after the transfusion for any adverse reactions. Vital signs should be checked frequently and any symptoms of discomfort or adverse reactions should be reported to the healthcare provider immediately.
It’s also important to remember that blood transfusions are a medical procedure, and it’s always a good idea to discuss the risks and benefits with your healthcare provider before receiving a transfusion.
How many diseases are caused due to malfunction of the blood?
There are a variety of diseases that can be caused by malfunctioning blood, let’s discuss some examples:
Anemia: a condition characterized by a lack of red blood cells or hemoglobin, which can lead to fatigue, weakness, and shortness of breath.
Hemophilia: a genetic disorder that affects the ability of blood to clot properly, leading to excessive bleeding and bruising.
Leukemia: a cancer of the blood and bone marrow, characterized by the uncontrolled production of white blood cells.
Sickle cell anemia: a genetic disorder that causes the red blood cells to take on a crescent shape, leading to blockages in small blood vessels, which can cause pain and organ damage.
Thalassemia: a genetic disorder that affects the production of hemoglobin, leading to anemia, fatigue, and organ damage.

Hemolytic anemia: a condition in which the red blood cells are destroyed faster than they can be replaced, leading to anemia, jaundice, and fatigue.
Blood clots: Blood clots can form in the blood vessels and can cause serious health problems, such as heart attacks, stroke, and deep vein thrombosis.
It’s important to note that these are just examples and there are many other blood-related disorders that can affect human health. If you have any concerns about your blood health, it’s important to consult with a healthcare professional.