Red cell autoagglutination is the process whereby red cells clump together forming aggregates. This is seen in Waldenström’s macroglobulinemia, cold agglutinin disease and Infection with Mycoplasma Pneumonia or Infectious mononucleosis. Autoagglutination represents clumping of an individual’s red blood cells (RBCs or erythrocytes) by his or her own serum due to the RBCs being coated on their surface by antibodies. #Clinical #Path #Blood #Smear #Microscopy #RBC #Autoagglutination