World’s Rarest Blood Type CRIB Blood Group 1 Discovered in India
The most recent and revolutionary finding is the CRIB blood group which was discovered as recently as 2025 in India. This blog is a thorough insight into one of the blood groups, the CRIB and its discovery, its scientific importance, clinical impacts and future scope and like every important point is discussed here.
The blood groups are important blood markers on red blood cells which determine compatibility in blood transfusion and play a pivotal role in numerous medical practices in the whole world.
Although the ABO and Rh blood group systems are the most widely recognized systems of blood groups, recent developments have increased our understanding by leaps and bounds.
What is the CRIB Blood Group? The only 1 woman in 8 billion people?
The CRIB blood group falls as part of the Cromer blood group system which is a less-recognized and highly important blood group system made up of antigens found in Decay-Accelerating Factor (DAF) protein and which is found on the surface of red blood cells. The CRIB acronym means:
- CR: Cromer (blood group system)
- I: India
- B: Bengaluru (the place where it was discovered)
What makes CRIB different from all other blood groups, ABO, and Rh blood groups is the lack of a high-prevalence antigen found in nearly all humans. This causes the blood of CRIB and individuals to be incompatible with all the traditional donor blood types, leading to extraordinary challenges to the field of transfusion and transplantation medicine.
The Scientific Pathway to Discovery
CRIB blood group was found by chance, when a patient underwent a routine pre-surgical test of a 38-year-old woman living in Kolar, near Bengaluru, Karnataka. Originally classified as O positive (the universal blood type), her blood bizarrely demonstrated pan reactivity- incompatibility with all of the identified blood groups then on the planet. The blood sample of even 20 members of the family did not match.
Her blood was thoroughly investigated at the Rotary Bangalore TTK blood Centre, one of the best immunohematology laboratories in India, and samples later sent to the International Blood Group Reference Laboratory (IBGRL) in Bristol, UK.
Molecular and serological analyses at the molecular and serological level over 10 months eventually led scientists to confirm that a new antigen existed in the Cromer blood group system, which will now be known as CRIB.
Verification and name promulgation of this novel blood group was announced at the 35th Regional Congress of the International Society of Blood Transfusion (ISBT) at Milan in June 2025 and mark a historic moment in transfusion medicine.
The differences between CRIB and ABO and Rh Blood Groups
Whereas the ABO system is based on sugar molecules physical property (A and B antigens) and the Rh system is based on the D protein antigen on red blood cell, CRIB is determined by the lack of nucleic (no specific glycoprotein antigen) within the Cromer system that relates to the DAF protein.
| Feature | ABO Blood Group | Rh Blood Group | CRIB Blood Group (Cromer System) |
| Basis | Presence of A & B sugar antigens | Presence of D antigen | Presence or absence of DAF protein antigen |
| Antigen Type | Carbohydrates | Protein | Glycoprotein (DAF-related antigen) |
| Clinical Importance | Defines transfusion compatibility | Prevents Rh hemolytic disease | Challenges transfusions due to antigen absence |
| Frequency | Universal | Widespread | Ultra-rare (only 1 known individual) |
| Discovery Year | Early 20th century | 1930s | 2025 |
Clinical Significance of CRIB Medical Significance
- Transfusion issues: CRIB individuals cannot accept blood donated by anyone who does not have the CRIB antigen, regardless of ABO and Rh compatibility, which has the effect of making blood transfusions very difficult.
- Prenatal implication: Blood incompatibility occurs with rare antigens such as the CRIB, which causes Hemolytic Disease of the Fetus and Newborn (HDFN) and therefore close prenatal screening and management are required.
- Organ transplantation: Compatibility is run before transplantation where it is important to get an accurate match based on immunogenetic and blood group matching.
- Development of rare donor lists: The finding supports the case of an inclusion of complete lists of rare blood donors and promotes the involvement of international organizations to respond to rare blood donor patients within a short time.
Influence on the Practice of Blood Donation and Healthcare
The finding of CRIB blood groups has promoted a paradigm shift in transfusion medicine in India and worldwide. The Rotary Bangalore TTK Blood Centre and the Karnataka State Blood Transfusion Council in conjunction with the Indian Council of Medical Research (ICMR), began a Rare Donor Registry to assist CRIB and other ultra-rare blood group patients.
The program is yet another move toward:
- Increasing the ability to use molecular diagnostics.
- Enhancing rare blood donation.
- Promoting international Joint Research to find more such rare antigens.
- Increasing the awareness of clinicians, transfusion specialists and policymakers regarding management issues of blood compatibility services in complex areas.
Looking beyond: The future of Personalized Medicine
It is an ongoing study to look more into the genetic establishment of CRIB, and more carriers are being identified. The state of the art in genetic sequencing technologies will:
- Disclose the population genetics, prevalence of CRIB and homologous rare types of blood groups.
- Support precision medicine practices with transfusion practices individualized to the antigen profile.
- Enlarge the international rare blood bank as a measure to attenuate the risk of transfusion.
- Enhance pregnancy, surgical and transplantation success via molecular blood typing.
Frequently asked questions revolving around the CRIB blood group
Exactly what is the CRIB blood group?
CRIB is a novel blood group discovered in the Cromer hemoglobin group that refers to the lack of a high-frequency antigen in almost all human beings.
How uncommon is CRIB?
It is as of now the most uncommon blood group that is recognized and only one individual in the world is verified to be of the blood type by 2025.
Is it easy to donate/ match CRIB blood?
No, CRIB patients need donors that have the same kind of blood match, and what they have is the same set of rare antigens, and this is not yet available globally.
What are the pregnancy and blood transfusions effects of CRIB?
CRIB inability takes place whenever there is an immune response to transfusions in addition to the possibility of resulting in a condition known as Hemolytic Disease of the Fetus and Newborn (HDFN) which happens as a result of removal of incompatibility.
Is CRIB confined to individuals of Indian origin?
The initial case was detected in India, yet with the continued study, CRIB carriers could be found in other locations because there is human genetic diversity.
1 in 8 billion CRIB Blood Group 1
The discovery of the CRIB blood group in India is an insurmountable step in the field of immunohematology that broadens our perceptions of human diversity in blood and offers a new frontier in the transfusion field.
Its breakthrough is innovative and India is the first country to do it and this just shows how Indian is becoming a leading country in global health research.
Given the acquired resource of CRIB, the healthcare systems across the globe are required to step forward to genetic blood typing, build up a strong network of rare donors, and integrate personalized solutions of transfusion and transplant.
In the end, this finding gives clinicians and researchers the ability to save more lives, and revolutionize patient care during an era of precision medicine.
