Perform an antibody identification using a group O panel.
Do the panel in saline phases at RT (or 4°C) since autoanti-I is an IgM antibody that reacts best in the cold.
As QC for the antibody identification, include an autocontrol and cord cells.
Expect all panel cells to be positive, as well as the autocontrol. Cord cells should be weakly positive or negative.
If an autoanti-I is identified, redo the ABO group at 37°C. The autoanti-I will not react at 37°C, but anti-A and anti-B should. Alternatively, because ABO antibodies may be weaker at 37°C, use autoadsorbed serum for the reverse group.