What is ABO typing?

By William Aird

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.

Interpretation of typing studies and prevalence of blood types. From the AABB.