An Overview

In the human body, blood plays a major role in the transportation of hormones, nutrients, respiratory gases, hormones, etc. It is known as the only fluid connective tissue, which is because blood cells develop connections between different organs.

Along with transportation, blood is also involved in different thermoregulation processes, maintains and regulates body temperature, pH and another body metabolism. As per scientists’ views and observations, the total volume of the blood in the human body should be about seven to eight per cent of the complete bodyweight, which will be about 5 to 5.5 litres or 1.5 gallons of blood.

What are Blood Groups? 

Blood groups, also called blood types, can be defined as the grouping of blood and are based on the presence or absence of genetically derived antigenic substances on the surface of red blood cells (RBCs). The antigenic substances may either be carbohydrates, glycolipids, proteins or glycoproteins, depending on the blood type system.

Karl Landsteiner, an Austrian scientist discovered the ABO blood group system in the year 1900. He was awarded the Nobel Prize for this discovery of his. 

A Blood group or blood type is a blood-classification, categorized on the basis of presence and absence of antibodies and genetically derived antigenic particles on the surface of RBCs. There are 4 main blood groups of human blood which are O, A, B, and AB, which is also called the ABO blood type. For a safe transfusion, a specific way should be followed to match the blood groups. 

  • Blood Group A– Presence of antigen A on the RBCs and antibody B in the plasma.

  • Blood group B– Presence of antigen B on the RBCs and A antibody in the plasma.

  • Blood group AB– Presence of both antigen A and B on the red blood cells and lacks the antibody.

  • Blood group O– Absence of both antigen A and B on the red blood cells and presence of both the antibodies A and B in the plasma.

Know the Different Types of Blood Groups along with its Rh Factor.

Blood Type 





Rh positive 





Rh negative 





There are numerous interesting facts about Blood Groups which we are not aware of. Some facts about the Blood Groups are listed in the points below.


A newborn baby has only one cup of blood in the whole body, whereas, the healthy adult has about 1.3 to 1.6 gallons or 4.0 to 5.0 litres of blood circulating inside their body


Blood type influences one’s personality, which can also affect your fertility and belly fat. Women with blood type O are more likely to deal with fertility issues.


The Red blood cells that do not contain either A or B antigens on their surface are normally found in the person with blood type O.


Anybody with good health, healthy weight and around the age of 17 years old can donate blood every 3 to 4 months.


By the process of blood transfusion, every year more than 4.5 million lives are saved 


No one can get AIDS or any other infectious disease by donating blood and donating blood takes less than 15 minutes.


Human blood has no other substitute and it makes 7 to 8 percent of total body weight.


Transfusion with a blood group different from yours can lead to complications.


In ABO blood type, a transfusion of AB blood group can be given to a person who has blood type A, B and AB.


AB blood type is known to be the “universal recipient” because AB+ people can accept blood from any other blood type. AB- is the least common blood type, which is less than 1% of the population. An individual with AB- blood type can receive blood from all three negative blood types.


O blood type is called to be the “universal donor” because O+ is the most frequently occurring blood group in the ABO type. About 37 to 40 percent of the entire population are found with this blood type. O- is the rare blood group as it is found in 6 to 7 per cent of the total population.


A+ is the third most frequently occurring blood type in the ABO system. Thirty people out of hundred people have A+ blood type. A- is the rare blood type, which is less than 10 to 15 percent of the population has this blood type.


Both B+ and B- are rare blood types and less than 10 percent of the population has this blood type.


Like hair colour, texture, and eye colour, blood type is also inherited or passed genetically from our parents. Therefore, our blood group is based on the blood types of either mother or father.


Blood Types and Compatible Blood Type Donors

Blood Type 

Receive Blood From 

Donate Blood To 


A+, A-, O+ and O-

A+ and AB+


B+, B-, O+ and O-

B+ and AB+


All blood types

AB+ only


O+ and O-

O+, A+, B+ and AB+


A- and O-

A+, A-, AB+ and AB-


O- only

All blood types


B- and O-

B+, B-, AB+ and AB-


AB-, A-, B- and O-

AB+ and AB-

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