What are red cell antigens and why do they matter?
What antigens are
Antigens are tiny markers on red blood cells. The well-known ones define the A, B, O, and Rh types, but there are many others.
Why frequent transfusions need closer matching
When someone receives blood many times, matching more of these markers reduces the chance of a reaction and keeps future transfusions easier to match.
How donors fit in
A large, diverse donor pool makes it more likely that a closely matched unit is available when a patient needs one.
Blood matching is complex. Similar ancestry can increase the chance of compatibility for some patients, but compatibility is determined by blood testing.
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This is general educational guidance, not a final eligibility decision. Donation centers make final eligibility decisions during confidential screening.
The guidance on this page reflects published criteria from these organizations. Eligibility and procedures vary by center and country, so confirm specifics with your donation center.
- American Red Cross Sickle Cell Initiative
- AABB: diversity in the donor pool
- American Red Cross: eligibility requirements
- Last reviewed:
- Next review due:
- Editorial review:
- Reviewed against American Red Cross, AABB, and U.S. FDA donor guidance
- Clinical reviewer:
- Not yet clinically reviewed
- Confidence:
- Medium confidence