Incidence of Antibodies Occurring in Healthy Donor Sera

A four‐year survey of the incidence of isoimmune antibodies in a volunteer donor population is reported. A yearly a verage of 0.34% of all units of blood was found to contain isoimmune antibodies. Antibodies were found in 0.56% of first time donors. The occurrence and types of antibodies as well as the screening method employed in their detection are outlined.