ABO antibody titer performance characteristics and correlates between two automated platforms

Area of Science:

• Transfusion Medicine
• Immunology
• Laboratory Science

Background:

• AABB standards mandate policies for assessing ABO-incompatible plasma transfusions.
• A fatal hemolytic event prompted the adoption of a platelet donor population titer method for ABO antibodies using the PK7300 platform.
• High-titer isohemagglutinin was defined as >256 on the PK7300.

Purpose of the Study:

• To determine the equivalent high-titer cutoff for isohemagglutinin on the Neo Iris platform compared to the PK7300.
• To evaluate the performance characteristics of the Neo Iris for antibody titering in apheresis platelet donors.

Main Methods:

• Titers were measured on 299 apheresis platelet donors using the Neo Iris platform.
• Performance characteristics were compared against the PK7300 reference standard.
• Discrepant results were retested on the Neo Galileo, and isotype/antigen-specific titers were characterized.

Main Results:

• An IgM titer of 128 on the Neo Iris demonstrated higher accuracy (94%) than a titer of 64 (93.6%).
• Blood group O donors exhibited the highest IgG antibody titers for both anti-A and anti-B.
• Group O donors showed lower anti-A2 than anti-A1 IgG titers.

Conclusions:

• A Neo Iris titer cutoff of 128 showed the best accuracy and correlation with the PK7300's 256 cutoff.
• Group O donors possess the highest antibody titers, predominantly IgG, exceeding those of other blood types.