In life-or-death situations, the perfect match matters. A single blood type can determine survival during emergencies, surgeries and treatments.

It is a known fact that compatibility in blood transfusions is determined by the presence or absence of specific antigens in red blood cells, as well as the rhesus or Rh factor that determines if a blood type is positive or negative.

When blood types match, the antigens are recognised as friendly, reducing the risk of adverse reactions.

Less known is the concept of personality types that are determined by blood groups, the analysis of which is termed “Ketsueki-gata”. In the 1930s, a Japanese professor named Tokeji Furukawa published a paper claiming that each blood type reflects the personality of the person who possesses it.

Then there’s research that suggests one’s blood type makes one more immune or predisposed to certain health conditions.

In conjunction with World Blood Donor Day today, here are some established facts – as well as posited traits to be read with a grain of salt – about one’s elixir of life. Either way, perhaps it’s time to roll up those sleeves and become heroes for fellow Malaysians in need.

Type A: the focused individual

Did you know that approximately 35% of Malaysians have blood type A? Their blood contains A antigens, making them a crucial lifeline for fellow type-A and AB individuals in need of transfusion.

In Malaysia, blood type A is most common among Malays, followed by Chinese and Indians. According to the National Blood Centre, just over a quarter (25.1%) of all donations are made up of type A.

When it comes to personality profile, those of this blood type are said to be sensitive and cooperative, emotional and intelligent. They tend to avoid conflict, are rule followers, and care about etiquette and social standards.

They also like to take their time to make decisions, tend to be hyper-focused on being organised, and aren’t good at multitasking. As such, many people with obsessive compulsive disorder (OCD) are said to be of this blood group.

Those with blood type A are said to have the highest levels of stress as they produce more cortisol, the stress hormone. They are also purportedly more predisposed to blood clots, memory loss, diabetes, and certain cancers, especially stomach cancer.

But here’s some good news: blood type A-positive is globally in high demand to treat cancer patients and premature babies, while doctors often depend on type A and AB plasma for trauma patients and accident victims.

Type B: the bold persona

Those of this blood group have red blood cells that bear B antigens, forging a bond with other type-B individuals as well as those of type AB. About 26% of the Malaysian population has this blood type.

Personality-wise, individuals with blood type B are often hailed as risk-takers and adventurers. They also very creative and quick decision makers, but may shy away from taking orders.

Recent studies have uncovered that blood type B may confer health benefits, including a lower risk of infections and inflammation. Those in the B-positive group are also said to have a lower chance of developing high cholesterol.

On the flipside, according to one study, those with B-positive blood have a 35% increased risk of diabetes. Type-B individuals may also be more susceptible to blood clots and heart disease.

The National Blood Centre reports that 27.6% of donations in Malaysia are of type B.

Type AB: the universal recipient

With only around 7% of the Malaysian population sharing this type, your red blood cells display both A and B antigens, granting you the title of a universal recipient.

But here’s the catch: AB individuals are limited in their ability to donate to others. Due to the aforementioned A and B antigens, those with type AB can only donate to fellow AB individuals.

And just like their blood group, those with type AB are said to have a mix of personalities: they might be shy like the A group, or outgoing like the B.

Research shows that those with type AB are 82% more likely to have memory problems than those of other blood types and, similar to type A, are more prone to stomach cancer and heart disease.

In Malaysia, the prevalence of blood type AB is observable among the Chinese population. But AB remains the rarest of the four groups at the National Blood Centre, at just 6.1%.

Type O: the universal donor

What sets blood type O apart is its unique status as the universal donor, as it lacks A or B antigens. This means that individuals with type O can give to recipients of any blood group, making their donations highly sought.

That said, those of blood type O can only rely on their own kind: lacking A and B antigens, their blood can be seen as foreign by other types.

From a personality perspective, those of this group are said to be daring, outgoing, and go-getters. They set high standards for themselves and possess strong leadership qualities.

Healthwise, out of all the blood groups, type O is said to bear the lowest risk of heart disease, cancers, and clots. That said, individuals with type O blood are more likely to experience more difficulty conceiving due to diminished ovarian reserves, or lower-quality and fewer eggs than normal.

Approximately 32% of Malaysians have this valuable blood type, while the majority (41.2%) of donations at the National Blood Centre are made up of Type O.

Rh-null: the extraordinary rarity

In a remarkable twist, Terengganu is home to a woman who possesses the rarest blood type in the world – Rh-null, which is referred to as “golden blood”.

With just 43 known individuals worldwide, this unique blood type lacks all Rh antigens, making it highly coveted for medical research and lifesaving transfusions in rare cases.

According to “Medical News Today”, the Rh-null blood type is unique owing to the absence of Rh antigens in the red blood cells.

Rh-null blood is both a risk and a lifeline, capable of saving countless lives while posing challenges to its host. For instance, having a rare blood type can make it difficult or even impossible to get a transfusion or organ transplant.

It can also cause other health issues – for example, if her blood is incompatible with a developing foetus, a pregnant woman with a rare blood type may experience complications.

Given only in extreme circumstances and after very careful consideration, Rh-null is treated as a highly precious resource. And, understandably, the woman from Terengganu has chosen to keep her identity a secret as the scarcity of her blood type makes her a subject of fascination.

Those interested in donating or who want more information can contact the National Blood Centre at 03-2613 2777 or visit its website.

Also read more on blood donation statistics in Malaysia via the health ministry’s online portal.