Inhibition of blood group antibodies by soluble substances

The presence of multiple alloantibodies or an antibody to a high-prevalance antigen in a patient sample can pose challenges in antibody identification. The pattern of reactivity seen on an antibody panel may show various strengths of reactivity by different methods of testing or same strength of reactivity at one or more phases of testing. To ensure proper identification, multiple investigative tools may be used. We review one of these methods—inhibition by soluble substances—which has become an expansion of our toolbox within the past 10 years. Alloantibodies can be inhibited using specific soluble substances. These soluble substances occur naturally in various fluids or can be manufactured. When a patient sample contains multiple antibodies, clinically significant or not, inhibition of one may help determine specificities of others. Specific inhibition of a particular antibody will also help to confirm its presence.