Testing for presence of A and B antigens on red blood cells:
- Forward typing – red blood cells (RBCs) are tested for A and B antigens.
- Reverse typing – serum or plasma is screened for presence of anti-A and anti-B antibodies.
According to a Circular prepared jointly by AABB, the American Red Cross, America’s Blood Centers, and the Armed Services Blood Program:
The ABO group of all red-cell-containing components must be compatible with ABO antibodies in the recipient’s plasma. Serologic compatibility between recipient and donor must be established before any red-cell containing component is transfused. This may be accomplished by performing ABO/Rh typing, antibody screening, and crossmatching by serologic technique or use of a computer crossmatch.
| ABO Group | Prevalence in US – European ethnicity | Prevalence in US – African ethnicity |
|---|---|---|
| 0 | 45% | 49% |
| A | 40% | 27% |
| B | 11% | 20% |
| AB | 4% | 4% |
