Abstract
Polyagglutination is a condition in which red blood cells (RBCs) are agglutinated by normal adult human sera but not by autologous or newborn sera. Polyagglutination is caused by changes in the RBC membrane that enable patient RBCs to agglutinate with normal human sera; this agglutination can interfere with blood bank testing. Depending on the cause, polyagglutination may or may not be the cause of RBC hemolysis. Lectins and human sera can be used to detect polyagglutinable RBCs. Identification of this phenomenon can be helpful in providing not only transfusion recommendation information for physicians but also information associated with pathogens (i.e., Streptococcus pneumoniae) and severity of illness. Testing with ABO group–compatible adult human sera can determine if a patient’s RBCs are polyagglutinable. Further testing with a variey of lectins may identify the kind of polyagglutination. Immunohematology 2018;34:113–117.