CRIB Blood Group Explained: Karnataka Woman Is World’s First With This Rare Type

In a significant breakthrough in the field of transfusion medicine, a previously unknown blood group has been identified in a woman from Kolar district, Karnataka. The blood type, now officially recognised as CRIB, has been confirmed as the first of its kind globally.

Patient’s Blood Baffled Experts

The discovery came to light when a 38-year-old woman from Kolar was admitted to a local hospital for cardiac surgery. Though her blood was initially classified as O Rh-positive, none of the available O-positive blood units were compatible with her. This unexpected incompatibility prompted the hospital to escalate the case to the Advanced Immunohematology Reference Laboratory at the Rotary Bangalore TTK Blood Centre for further analysis, as reported by The New Indian Express.

Dr Ankit Mathur from the Rotary Bangalore TTK Blood Centre explained, “Using advanced serological techniques, our team found that her blood was ‘panreactive’, incompatible with all test samples. Recognising this as a possible case of a rare or unknown blood type, the team collected blood samples from 20 of her family members to search for a compatible match, but none of them were a match. The case was managed with utmost care, and with collaborative effort from her physicians and family, her surgery was successfully completed without the need for transfusion.”

CRIB Blood Group Named to Honour Origin

The woman’s and her relatives’ blood samples were sent to the International Blood Group Reference Laboratory (IBGRL) in Bristol, UK. Following ten months of intensive molecular testing, researchers confirmed the presence of a novel blood group antigen, now named CRIB — derived from the Cromer (CR) blood group system, with ‘IB’ representing ‘India, Bangalore’. The announcement was made during the 35th Regional Congress of the International Society of Blood Transfusion (ISBT) in Milan, Italy, in June 2025.

“This historic finding marks her as the first person in the world identified with the CRIB antigen,” said Dr Mathur.

Medical Significance and Global Implications

As per India Today, the CRIB blood group is categorised under the Indian Rare Antigen (INRA) system, officially recognised by ISBT in 2022. Unlike major systems such as ABO and Rh, CRIB is characterised by the absence of a high-prevalence antigen found in most individuals. This absence makes transfusions extremely challenging, as only blood from another CRIB-negative individual would be compatible.

The blood group’s relevance extends to fetal-maternal medicine, particularly in preventing Hemolytic Disease of the Fetus and Newborn (HDFN), a condition where the mother’s antibodies destroy the fetus’s red blood cells. Early identification of the CRIB group could play a pivotal role in preventing such complications.

India’s Role in Rare Blood Discoveries

India’s genetically diverse population continues to contribute significantly to global medical research. The INRA system itself was first discovered in an Indian woman in 2017. The emergence of CRIB further highlights the need for enhanced screening programmes, genetic studies, and the expansion of rare blood donor registries across the country.

The Rotary Bangalore TTK Blood Centre has since launched a Rare Donor Registry in collaboration with the Karnataka State Blood Transfusion Council and the ICMR’s IIH centre in Mumbai, with technical support from ISBT.

“We have been instrumental in identifying and providing optimal transfusion support to several other rare blood type patients in recent years. These cases have also been published and presented to international forums (eg: D- -, Rh null, In b negative etc),” added Dr Mathur.

Researchers are now advocating the development of CRIB-specific antibody panels and enhanced screening techniques to help detect potential carriers early. The discovery serves as a reminder of how much remains to be uncovered in the realm of human biology.