Know Your Blood Group & Rhesus Factor: Prevent Incompatibility
Have you ever asked yourself what it means when your doctor tells you that your blood group is A+ or B–? What is the significance of these symbols: A, B, O, AB, Rh+, Rh–? Why obtaining a blood group certificate is a must for driving license applicants? Rest assured. All these questions and a lot more will be answered in this article.
What is ABO Blood Group System?
Blood typing is a test to determine a person’s blood type. Blood group is a classification of blood based on the presence or absence of blood antigens on your red blood cells and antibodies in your blood plasma. Antigens are cell expressions that lead to production of antibodies, our own immunity to the presence of foreign substance (antigen).
Did you know that ABO blood group system was first identified by the Austrian scientist Karl Landsteiner over 100 years ago? He attained a well-deserved nobel prize for the discovery!
There are four main blood groups: A, B, AB, and O. People with A blood group have A antigen on their red blood cells and B antibody in their plasma. Antibodies are what attacks foreign cells, an important part of our immunity. People with B blood group have B antigen on red blood cells and A antibody in blood plasma. People with AB blood group have A and B antigens on red blood cells and do not have antibodies in blood plasma. People with O blood group do not have any antigens on red blood cells and have A and B antibodies in blood plasma.
From the previous explanations, you may reach the logic conclusion that O blood group is considered as a universal donor and people with AB blood group are universal recipients.
What is ABO Incompatibility?
Blood test is a must before any blood transfusion to avoid ABO incompatibility reactions. They are dangerous and potentially deadly responses to incompatible blood by your immunity. Within few minutes of receiving a mismatched blood group, you may feel these symptoms: high body temperature, difficulty in breathing, chest pain, blood in your urine, nausea, and abdominal pain. You have to enter into the intensive care unit as soon as possible. You may receive oxygen, intravenous fluids, and medications to increase your urine output.
In organ transplants, only ABO-compatible grafts (matching blood groups between donor and recipient) are advised to prevent rejection. Low rates of success have been achieved in ABO-incompatible organ transplants in adults. If your blood contained antibodies that reacted to your donor’s blood type, the antibody reaction would immediately cause you to reject the organ transplanted, thus preventing a successful transplant.
Prevalence of ABO Blood Groups
The most common blood type all over the world is blood group O, especially among peoples of South and Central America. Blood group B is prevalent in Asia, particularly in northern India, and south Asia. Blood group A also is common throughout the world; the highest frequency is among Australian Aboriginal peoples, the Blackfoot Indians of Montana, and the Sami people of northern Scandinavia.
What is Rh Blood Group System?
Rh typing, which is considered for many scientists as complementary to ABO blood group, is based on detection of specific antigens on your red blood cells. Generally, ABO and the Rhesus test are performed together.
If rhesus antigen are present on your red blood cells, you are considered Rh+. If your red blood cells do not express any rhesus antigen, you are considered Rh–. If your blood is Rh+, you can receive Rh+ or Rh– blood transfusions. But, if your blood is Rh–, you can only accept Rh– donors because your body will identify the Rh antigens from the donor blood (Rh+) and launch an immune reaction to it, leading to serious transfusion reaction.
People with O– blood are called “universal” red cell donors because they can give blood to anyone with any blood type, so if you do not know your ABO and need highly urgent transfusion, the hospital will likely transfuse with O– blood.
Approximately 10-15% of the population lack Rh factor (Rh-). The other 85% of people are Rh-positive.
Rh and Pregnancy
All pregnant women should take the Rh factor test during the first prenatal screens. It is one of the main, first and most important tests for all pregnant women.
If you are Rh+, you are in the safe zone. However, if you are Rh– and your baby is Rh+, your baby might be in a grave danger. When your blood comes in contact with the baby’s blood, your body will make antibodies to attack the baby’s red blood cells, causing anaemia and other serious problems. This medical condition is known as erythroblastosis fetalis.
Your doctor will give you a shot of Rh immunoglobulin to prevent occurrence of this serious medical condition. You may need another dose shortly after delivery. This medication prevents your body from making antibodies.
Putting the pieces of puzzles together, you can now understand what is meant if your doctor told you that your blood group is B+. This means that you have B antigens on your red blood cells, A antibodies in your plasma, and Rh factors on your red blood cells. Believe it or not, identification of ABO, and Rh blood group systems is considered one of the most important discoveries, which has great effects on human health and welfare.
If you’re interested in learning more about blood grouping and rhesus factor, read on more about it in our biomarker post here!