Blood donation remains the primary source of blood and a single pint can save up to three lives. — Filepic
Blood is the lifeline of the human body, playing a crucial role in transporting oxygen, nutrients and waste products.
However, not all blood is the same.
Blood grouping is a fascinating and vital aspect of biology and medicine that helps ensure safe transfusions and organ transplants.
Once you explore the basics of blood groups, their significance and some interesting facts, you’ll be surprised at how remarkable this life-sustaining fluid truly is.
The concept of blood groups was first discovered by Karl Landsteiner in 1901, earning him the Nobel Prize in Physiology or Medicine.
Our blood is categorised into groups based on the presence or absence of specific antigens on the surface of red blood cells (RBCs).
Antigens are molecules that trigger immune responses, and their composition varies between individuals.
The two primary blood grouping systems are:
> ABO System
This system categorises blood into four main types:
Type A: Has A antigens on the RBCs and anti-B antibodies in the plasma.
Type B: Has B antigens on the RBCs and anti-A antibodies in the plasma.
Type AB: Has both A and B antigens but no anti-A or anti-B antibodies, making it the universal plasma recipient.
Type O: Has no antigens but both anti-A and anti-B antibodies, making it the universal donor.
> Rhesus (Rh) System
The Rh system is determined by the presence (Rh-positive) or absence (Rh-negative) of the Rh factor, another antigen on RBCs.
For instance, a person with A-positive blood has A antigens and the Rh factor, while someone with A-negative blood lacks the Rh factor.
Besides ABO and Rh, there are over 30 other blood group systems recognised by the International Society of Blood Transfusion.
The important ones include:
> Kell System
Involves the Kell antigen, which can cause severe transfusion reactions and hemolytic disease of the newborn (HDN).
> Duffy System
The Duffy antigens are receptors for certain malaria parasites, making Duffy-negative individuals resistant to these infections.
> Lewis System
Associated with antigens secreted into body fluids and absorbed onto RBCs.
> MNS System
Comprises multiple antigens that vary among populations and are relevant in transfusion medicine.
Despite advances in medical science, we are still unable to synthesise human blood.
The complexity of blood lies in its unique components and functions:
> Diverse cellular composition
Blood contains RBCs, white blood cells (WBCs), platelets and plasma, each performing distinct roles such as oxygen transportation, immune defence, and blood clotting.
> Dynamic interactions
The interactions between these components are intricate and vital for maintaining homeostasis (a state of balance in the body system).
> Individual specificity
Blood groups and antigens vary widely among individuals that comes with another layer of complexity.
Synthetic alternatives are unable to replicate this diversity successfully to date albeit the advancement in technology including artificial intelligence.
> Lifespan of components
Blood cells have a limited lifespan (e.g. RBCs last about 120 days), therefore requiring continual replenishment that synthetic blood struggles to mimic.
Thus, donations remain the primary source of blood which highlights the importance of volunteer donors.
These are reasons why blood grouping matters:
> Safe blood transfusions
Transfusions require compatibility between donor and recipient blood to prevent adverse reactions.
For example, a Type A person cannot receive Type B blood as the anti-B antibodies in their plasma would attack the incoming RBCs which will cause the cells to clump in a process known as agglutination.
> Pregnancy and Rh incompatibility
A Rh-negative mother carrying a Rh-positive baby can face complications due to Rh incompatibility. This is managed with Rh immunoglobulin injections.
> Organ transplants
Blood group compatibility is crucial for successful organ transplants, as mismatched antigens can lead to organ rejection.
> Personalised medicine
Certain blood groups are linked to susceptibility to specific diseases, influencing medical treatments and preventive strategies.
> Universal donors and recipients
Type O-negative individuals are universal donors as their blood can be safely given to anyone.
Type AB-positive individuals are universal recipients, as they can receive blood from any group.
> Rare blood types
The rarest blood type in the world is Rh-null, also called “golden blood,” with fewer than 50 known individuals globally.
Locally, a Terengganu woman is among the very few people in the world with this rare blood type. She became an online sensation after her story was published in the media a few years ago.
> Blood type and diet
Some people believe that your blood type can influence the best diet for you, though this theory lacks substantial scientific backing.
> Geographic distribution
Blood group distribution varies globally.
For example, Type B is more common in Asia, while Type O is predominant among Native Americans.
> Blood type and personality
In Japan, people often associate blood types with personality traits.
For instance, Type A is seen as organised and meticulous, while Type O is considered outgoing and confident.
> Animal blood groups
Animals also have blood types – dogs have over 12 blood types, while cats have three (A, B, and AB).
> Mosquito preference
Studies suggest that mosquitoes are more attracted to individuals with Type O blood compared to other types.
> Blood donation saves lives
A single pint of donated blood can save up to three lives, highlighting the importance of regular blood donation.
Determining your blood group is easy and involves a simple test where your blood is mixed with antibodies against A and B antigens.
Observing whether the blood clumps helps identify your group.
Blood grouping is typically performed in hospitals, blood donation drives, or specialised laboratories.
In essence, blood grouping is a cornerstone of modern medicine, ensuring safety and efficiency in transfusions, surgeries and organ transplants.
Beyond its medical importance, the diversity of blood groups offers intriguing insights into human biology and history.
Whether you’re a universal donor or have a rare blood type, understanding your blood group is crucial as it might even reveal some surprising connections to your health and heritage.
So, the next time you hear someone mention blood groups, compare it with your own blood group.
My blood group is B-positive, what’s yours?
Dr Lee Tze Yan is a senior lecturer and researcher in the field of biomedical science at the Institute of Medical Science Technology, Universiti Kuala Lumpur (UniKL). For more information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this article. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.