Medical Awareness >>   Blood Groups

Blood Groups


The human circulatory system includes the heart, blood vessels and blood. Oxygen and nutrients are carried to every cell in our bodies by blood. Blood also picks up waste products (such as carbon dioxide) to remove from the body. 

A bulk of blood is made of plasma. RBCs, a.k.a red blood cells float in the plasma that carries oxygen, WBCs or white blood cells form a part of our immune system, and the clotting cells are called the platelets. 

There are two major ways to classify blood groups: the ABO and the Rh systems. Other blood group systems also exist. More than 300 minor blood groups have been identified to this date, with new antigens still being discovered. 

A, B, O, and AB are the four principal blood groups. The genes determine a person's blood group they inherit from their parents. Every blood group can be either RhD positive or negative. All together, they make up 8 main blood groups. 

Types of Blood Groups 

A person's blood group is determined by a pair of genes - a single gene inherited from each parent. Each blood group is identified by its own set of molecules (also known as antigens) located on the surface of red blood cells. When a person needs a blood transfusion, the donated blood must match the recipient's blood; if not, there will be complications. The ABO system defines 4 main blood groups as below. 

  • Group A - with antigens A and anti-B antibodies in the plasma
  • Group B - with antigens B and anti-A antibodies in the plasma
  • Group O - with no antigens, but with both anti-A and anti-B antibodies in the plasma
  • Group AB - with both A and B antigens, but no antibodies 

Blood group O is the most general blood group and can safely be given to any other group. Obtaining blood from the incorrect ABO group can be a threat to life.

A Group B person must never give blood to Group A and vice versa. 

Blood types of humans are also categorized as Rhesus type, now we call it 'Rh type.' Your Rh type is determined by a different pair of genes. 

Blood can be either Rh-positive or Rh-negative, based on whether certain molecules are present. Rh-negative people will experience a severe immune-system reaction if Rh-positive blood gets into their bloodstream. Sometimes, the red blood cells have another antigen, known as the RhD antigen. If this exists, then the blood group is RhD positive; if not, the blood group is RhD negative. 

One can be any one of the following eight blood groups: 

  • RhD positive (A+)
  • RhD negative (A-)
  • B RhD positive (B+)
  • B RhD negative (B-)
  • O RhD positive (O+)
  • O RhD negative (O-)
  • AB RhD positive (AB+)
  • AB RhD negative (AB-) 

O- can be administered in medical emergencies when the blood group is unknown. It is safe for most utmost receivers because it does not have an A, B, or RhD antigens on the cells covering and is most compatible with every other ABO and RhD blood group. 

Donating Blood 

Donating blood is a simple and safe way to make a big difference in people's lives. Keeping yourself informed of the process before, during, and after you donate blood can help you prepare for the process. Most people can give blood, but only 1 in 25 people do. 

Who gets the benefit out of blood donations? 

  • Those who are victims of disasters or emergency situations
  • Those who lose blood during major surgeries
  • Those who lose blood due to a gastrointestinal bleed
  • Women who have serious complications during pregnancy or childbirth
  • People with cancer or severe anemia Benefits for people who regularly donate blood are:
  • Donating blood lowers excessive iron levels in our body
  • Better cholesterol and triglyceride levels
  • Emotional advantages of feeling happy and content from knowing you helped someone else 

One can donate blood if one is: 

  • Fit and healthy
  • Weigh at least 50kgs
  • eligible with a good hemoglobin level
  • are above 17 years of age How often can one donate blood?

If one donates whole blood, they need to wait 56 days between donations, or even longer. If one is donating platelets, they can do this every 7 days, up to 24 times a year. 

Side Effects After Donating Blood: 

While there are no lasting side effects, one might temporarily: 

  • Need to hydrate for 24-48 hours after you donate
  • Need to take it Don't work out or do any strenuous physical activity for 24 hours after donating blood.
  • Feel lightheaded. Lie down for a while until you feel
  • If you have a little bit of bleeding from the spot where you donated, raise your arm and apply pressure to that area for a few
  • If a bruise has been caused, apply ice on 
Fact Sheet: 
  • One has more than a gallon of blood in their
  • Blood group O is a universal blood
  • AB group is the universal blood
  • O and A groups are always in high
  • There is no best blood
  • ABO typing test determines the blood group where the blood sample is mixed with antibodies against type A and type B If blood cells stick together, it states that the blood reacted with one of the antibodies. 
PGC Resolution: To conduct Blood Testing and Donation drives to ensure a sufficient supply of blood to needy patients.