Albumin-indirect antiglobulin test

Albumin was the first widely used additive solution for hemagglutination tests. Its major effect is to decrease the repulsive forces that keep red blood cells (RBCs) apart. This effect may enable some RBC antibodies, particularly those in the Rh blood group system, to directly agglutinate antigen-positive RBCs after 37°C incubation. The impact of albumin on antibody binding before detection by an indirect antiglobulin test (IAT) is minimal. Use of albumin in antibody identification may help with separation of RBC antibody specificities in a mixture when one or more antibodies demonstrate reactivity after 37°C incubation. Warm autoantibodies can show decreased reactivity in albumin IATs, allowing recognition of underlying alloantibodies.