Rare Blood Group: CRIB

A 38-year-old woman from Kolar has been identified with a never-before-seen blood group, officially named CRIB, marking a global milestone in transfusion medicine.

About CRIB

• Discovery: Detected at Rotary Bangalore TTK Blood Centre after her blood showed “panreactive” behavior, meaning it was incompatible with all tested samples.
• International Validation: Confirmed by the International Blood Group Reference Laboratory (IBGRL), UK, after 10 months of molecular and antigen testing.

• Nomenclature: Named CRIB – CR for Cromer blood group system, and IB for India, Bengaluru – at the 35th ISBT Congress (Milan, 2025).
• Unique Feature: Represents a new antigen within the Cromer system, making her the first person globally to present with this antigen.

What is a Blood Group?

A blood group is classified based on specific antigens present on the surface of red blood cells. These antigens determine compatibility for transfusions.

Types of Blood Groups and Associated Antigens

• Antigens are molecules, usually proteins or sugars, found on the surface of red blood cells that can trigger an immune response.
• The Rh(Rehsus) factor is a protein found on the surface of red blood cells. If the protein is present, the blood type is Rh-positive; if it’s absent, the blood type is Rh-negative

What Are Rare Blood Groups?

• Definition: Rare blood groups occur when individuals lack “high-frequency” antigens found in most populations, making it difficult to find compatible blood for transfusion.
• Global Prevalence: Classified as:
  • Less Rare: 1–2% prevalence.
  • Very Rare: <1%, often involving 3–4 missing antigens.

Examples of Rare Blood Groups in India and Worldwide

• Rh null (“Golden Blood”): Absence of all Rh antigens.
• D- – Blood Type: lacks common Rh antigens, extremely rare.
• In b Negative : absence of Indian system antigen.
• Gwada Negative : Identified recently in Guadeloupe.
• Bombay Blood Group (hh Phenotype): Lacks h antigens  which are found across  A, B and O Group.
• CRIB: Newly discovered Cromer antigen from India.

Need for a Rare Blood Donor Registry in India

• Patients with rare groups develop antibodies against missing antigens, making transfusion matching difficult.
• Current Efforts: Rotary Bangalore TTK Blood Centre and partners launched a Rare Blood Donor Programme (2024).
  • It aims to build a national registry integrated with e-Rakt Kosh.
    • Out of 2,108 O-group donors, 21 rare types were identified.
• Future Approach: Use of  autologous transfusion or iron supplementation for planned surgeries in rare-group patients.
  • Autologous transfusion is a procedure where a patient’s own blood is collected, stored, and re-infused during surgery or treatment.