THE O+ve Blood Group: The Enigma in Plain Sight
There’s no dearth of strange blood groups in India. The blood type O positive (O+) falls under the ABO and Rh systems. In the ABO system, type O means red blood cells lack both A and B antigens, while the Rh-positive means that the Rh (D) antigen is present. Globally, this remains one of the most common blood groups, accounting for roughly 37-38% of people in many populations.
Seeing as O-type red cells have no A or B antigens, O blood can be given to any ABO type, but the Rh factor matters. O positive can only donate to people with Rh positive blood types (O+, A+, B+, AB+)
Blood type O positive (O+) is one of the most common and medically significant blood groups in the world. It is defined by the absence of A and B antigens and the presence of the Rh (D) antigen on red blood cells. This unique combination makes it highly valuable for transfusions and emergency care. While not a universal donor, such as O Negative, O Positive plays a unique role thanks to its widespread availability and compatibility.
Who Can Receive or Donate O Positive Blood - A Quick Compatibility Breakdown -
O Positive donors can give red blood cells to any individual that has an Rh-positive blood type that includes A+, B+, AB+, and, of course, O+. However, they can receive blood only from O+ or O- donors. This compatibility pattern makes O+ extremely important for routine hospital use, where we see that Rh-positive patients are in the majority.
Why do blood banks always need O positive?
O Positive may not grab headlines just like rare blood groups, but its commonness is exactly why it is always in demand. Hospitals and trauma centers rely on it for surgeries, childbirth-related transfusions, accident cases, and chronic illnesses. Power Red donations from
Does Your Blood Type Affect Health? What Does Science Say?
People with blood type O (positive or negative) tend to have lower risks of coronary heart disease and certain cancers, such as pancreatic and gastric cancer, according to certain studies. On the flip side, though, they are more prone to ulcers due to higher levels of stomach acid. The concept of “blood type diets” has been around for years, but remains unsupported by scientific consensus.
How Common is O+ve Around the World?
In many populations, O Positive remains the most common blood type, consisting of around 37% to 53% of individuals, all depending on region and ethnicity. In India, it is highly prevalent, which is why it forms a major share of blood bank inventory. Because it has a wide distribution, this ensures that the most Rh-positive individuals have O+ as a compatible donor option.
India Makes Global Headlines as Kolar Woman’s O+ Blood Reveals Hidden Antigen
In what seems like a medical anomaly, scientists at the 2025 International Society of Blood Transfusion Congress announced the discovery of a previously unknown blood group antigen named CRIB in a 38-year-old woman from Kolar, Karnataka. Though initially typed as O Rh+, her blood caused incompatibility issues during cardiac surgery, requiring further investigation.
The woman’s blood sample, analysed at Bangalore’s Rotary TTK Blood Centre and later confirmed by the International Blood Group Reference Laboratory in the UK, showed that it is a completely unrecognised antigen.
This shocked the transfusion science community, as it showed that even common blood types can carry rare and unidentified antigens.
Why The CRIB Antigen Discovery Changes Everything in Transfusion Science?
According to the CRIB antigen case, current blood typing might miss rare antigens, which translates into potential risks for patients undergoing major surgeries or multiple transfusions. This finding urges hospitals to go beyond ABO and Rh systems when cross-matching, particularly in regions that have genetically diverse populations, such as India. It also calls for an expanded donor registry for rare blood profiles.
What Does This Discovery Mean for O Positive Donors and Recipients?
For the majority of O+ individuals, previous compatibility rules remain unchanged. However, there are new conversations around antigen profiling.
It is possible that there are other hidden antigens in routine donors. If more CRIB cases surface, we just might see updates in blood screening methods, as well as targeted outreach for antigen-type donors.
Going Beyond Giving Blood - How O+ve Donors Can Help?
O Positive donors are considered the most valuable for blood banks. If you by any chance have this blood type, consider regular donations or double red cell procedures (Power Red). If you have had unusual reactions to transfusions in the past, you may ask to be screened for rare antigens, helping build a safer and more personalised transfusion database.
Busting Myths and Answering Common Questions About O Positive
Is O Positive a universal donor? No, but it can be given to any Rh-positive recipient
Can an O+ person receive blood from A+, B+, or AB+? No—they can only receive blood from O+ or O− donor
How rare is the CRIB antigen? At the moment, only one case is known worldwide—in the Kolar woman.
What’s Next for Transfusion Medicine After the CRIB Discovery?
This discovery underscores the need to:
Expand antigen screening.
Build rare blood registries in India and globally.
Conduct genetic research to understand how such rare antigens develop.
Push for policy updates in transfusion protocols, encouraging labs to go beyond ABO/Rh typing
Final Thoughts: O Positive Holds Secrets
While O Positive might be described as ordinary, the Kolar woman’s case proves that when it comes to our blood, it truly is special. Beneath the surface of even the most common blood types, there are secrets that reshape our understanding of human biology and transfusion science.
As blood donation awareness grows, O+ individuals can play a key role—not just as everyday donors, but as potential holders of lifesaving genetic information. Every drop counts, and every type matters.