Indirect antiglobulin test

Also known as IAT. This is previously referred to as the indirect Coombs test and sometimes referred to as an antibody screen. The IAT is an agglutination assay for detecting unbound antibodies present in a person's serum. It can be used to detect IgG antibodies present in sera (which are not directly bound on the person's red blood cells) as well as to "crossmatch" blood prior to a transfusion.