An Anti-I Cold Auto-Agglutinin Enhanced in the Presence of Sodium Azide

Abstract

Difficulty in determining the ABO blood group led to the discovery of an anti-I cold auto-agglutinin in the serum of a blood donor. The peculiarity of this antibody is that its activity is enhanced in the presence of a preservative found in manufactured anti-sera: sodium azide. At 4°C, the auto-antibody agglutinates RBCs even without NaN(3) but the drug increases its effect in the cold. At 22°C, the drug is necessary for the adsorption of the antibody on red cells.

In vitro reactions with red blood cells that are not due to blood group antibodies: a review

“…Reviron et al 39 described an anti-I cold agglutinin that was enhanced (the anti-I reacted at 4°C but not at 22°C, without sodium azide being present) in the presence of sodium azide. This led to difficulty in determining the ABO type of the patient when the patient's unwashed RBCs were tested with ABO-typing sera containing sodium azide.…”