When it comes to blood types, A, B, AB, and O are the ones everyone knows. But have you ever heard of a blood type that’s so rare, only one person in the world has it? That’s the CRIB blood group — a brand-new blood type discovered in India.
It was found in a woman from Kolar, Karnataka, and this blood group doesn’t match any known type.
This makes CRIB the rarest blood group in the world.
How Was It Discovered?
A 38-year-old woman from Karnataka was preparing for heart surgery. Her blood type was marked as O Rh+, which is common. But when doctors searched for a matching donor, no sample worked — not even her own family’s.
Through the use of sophisticated serological methods, the researchers discovered that her blood was “panreactive,” meaning it was incompatible with every test sample. The researchers thought that this might be an uncommon or unknown blood type, so they took blood samples from 20 members of her family to see if they could find a match. However, none of them did.
Her procedure was eventually carried out without a transfusion, which is rarely seen. The case reached Rotary Bangalore TTK Blood Centre and then IBGRL in the UK. 10 months later, researchers confirmed a new antigen.
The finding was formally announced at the 35th ISBT Congress in Milan in June 2025. This antigen was added to the Cromer blood group system, and the new type was officially named CRIB.
The CRIB Blood Group
CRIB (Chromosome Region Identified as Blood group) an antigen profile that has not been previously documented and does not correspond to any of the 43 blood group systems listed by the International Society of Blood Transfusion (ISBT).
In 2022, the ISBT formally accepted it as a member of the INRA (Indian Rare Antigen) blood group system.
The lack of a common antigen present in the majority of persons is what distinguishes CRIB. A hitherto unidentified antigen in the Cromer blood group system—which is connected to proteins on red blood cells—was identified as the cause.
The name CRIB comes from:
CR – Cromer blood group system (a group of rare antigens found in red blood cells)
IB – India and Bangalore (the place where it was discovered)
So, CRIB = Cromer + India + Bangalore.
The name honors the discovery made by Indian scientists at the Rotary Bangalore TTK Blood Centre.
Why Is the CRIB Blood Group So Important?
It’s Extremely Rare
Only one person in the world has this blood group. That makes it the rarest blood type ever recorded.
No Compatible Donors
She cannot receive blood from anyone else unless they also have CRIB. This makes transfusions very risky.
A Medical Breakthrough
This discovery can help doctors:
- Improve blood transfusion safety
- Handle organ transplants
- Prevent pregnancy complications
- Study rare genes and human biology
A Proud Moment for India
It’s the first time such a blood group has been discovered — and it happened right here in India.
Other Rare Blood Groups Around the World
*Bombay Blood Group (Hh or hh)*
First found in Mumbai, this type lacks the “H antigen,” meaning it doesn’t fit into A, B, AB, or O categories. Individuals with this blood group can only receive from the same type. It’s extremely rare — as few as 4 per million people have it.
*Rh-null (Golden Blood)*
Known as the “golden blood,” this type totally lacks Rh antigens. Fewer than 50 people worldwide are known to have it. It’s the rarest and most valuable blood type for transfusions — but incredibly hard to source.
Gwada Negative
Recently recognized as the 48th blood group by ISBT, this is unique to one known woman in Guadeloupe. She’s only compatible with herself for transfusions.
Er Blood Group System
The 44th officially described system. Discovered in the UK, its antigens can impact prenatal and transfusion medicine. It was identified after rare antibodies were detected during pregnancy complications.
Vel-negative
Individuals lacking the Vel antigen are very rare (found in only about 1 in 1,200 people in Sweden). Having anti-Vel antibodies can cause serious transfusion reactions, making compatible blood critical.
Facts About CRIB Blood Group
Why These Rare Blood Types Matter to You
Every Blood Type Is Unique
If someone labelled as a common type turns out to have CRIB, rare blood types can hide in plain sight.
Better Care for All
Even if you have a common blood type, research into these rare types improves tested safety for everyone — in surgeries, transplants, and maternal health.
Pride in Science
India’s role in discovering CRIB shows how local breakthroughs can lead to global impact in transfusion medicine.
Your Donation Could Save Lives
Rare blood groups like Bombay or Rh-null rely on donors. You may help someone with a rare condition you never knew existed.
It also shows the importance of medical research, testing, and global cooperation.
Final Thoughts
The CRIB blood group isn’t just a rare medical case — it’s a breakthrough discovery that places India at the center of global medical research.
Doctors, scientists, and healthcare centers worldwide are now studying CRIB to help those with rare blood types in the future.
Together with other rare blood types like Rh-null and Bombay, these discoveries underscore the need for research, rare donor networks, and the power of each blood donation.
