The application of eosin maleimide-binding test in the diagnosis of hereditary spherocytosis among undiagnosed cases of chronic hemolytic anemia in children

Background Conventional diagnosis of hereditary red blood cell (RBC) membrane disorders, in particular hereditary spherocytosis (HS), is labor intensive, time consuming and requires at least 2 ml of blood, which might be impractical in the neonatal period. Participants and methods We evaluated the use of eosin-5-maleimide (EMA) as a rapid screening test for patients with HS. RBCs from 74 healthy controls and 66 anemic children (35 HS and 31 other hemolytic anemias; 10 cases diagnosed as thalassemia, eight cases of autoimmune hemolytic anemia, one case of ovalocytosis and 12 cases of undiagnosed hemolytic anemia) were stained with EMA and analyzed for their mean fluorescence intensity using flow cytometry. Results RBCs from patients with HS showed a greater degree of reduction in mean fluorescence intensity of EMA compared with those from normal controls and patients with other hemolytic diseases. These findings showed that the fluorescence flow cytometric-based method is a simple, sensitive and reliable diagnostic test for RBC membrane disorders using a small volume of blood, and results could be obtained within 2 h. Such a method could serve as a first-line screening for the diagnosis of HS in routine hematology.