Eosin-5-maleimide used instead of cryohaemolysis to screen for hereditary spherocytosis.
Flow cytometric analysis of Eosin-5-maleimide (EMA)-labelled intact red blood cells has a high sensitivity (~93%) and specificity for red cells of HEREDITARY SPHEROCYTOSIS (HS). The predominant binding of EMA to band 3 can be attributed to the high abundance of this protein compared with other EMA-reactive RBC membrane proteins (Rh proteins, Rh glycoprotein, CD47). The test is also able to detect RBCs of HEREDITARY PYROPOIKILOCYTOSIS (HPP). The mean cell volume may be a useful discriminator for HS and HPP. [If Eosin-5-Maleimide test is negative, cryohaemolysis testing should be performed.]