A Comparative Evaluation Of Eosin-5-Maleimide Flow Cytometry Reveals A High Diagnostic Efficacy For Hereditary Spherocytosis

IntroductionLaboratory diagnosis of hereditary spherocytosis (HS) relies on increased incubated red cell osmotic fragility test for screening. We evaluated the diagnostic role of eosin-5-maleimide (EMA) binding test by flow cytometry in spherocytic and microcytic hypochromic hematological disorders in North Indians.MethodsEMA binding test using flow cytometry was performed on 55 HS (40 families), 26 iron deficiency anemia (IDA), 32 -thalassemia trait (TT), and 10 autoimmune hemolytic anemia (AIHA) cases and 121 normals. Mean channel fluorescence (MCF) and coefficient of variation (CV) were studied. Different MCF parameters (MCF, MCF ratio, percent decrease MCF) and percent increase in CV were analyzed. Receiver operating characteristics analysis was performed to determine best cutoff values, sensitivity, and specificity for discriminating HS from other red cell disorders.ResultsMCF ratio of HS group was significantly lower than normals (0.67 0.07 vs. 1.01 +/- 0.05, P < 0.001) and other cases. All patients with HS showed MCF ratio to be 0.79. Four postsplenectomy cases with near-normal hemograms also revealed low MCF ratio, showing the specificity of the test.ConclusionsEMA assay was efficient to diagnose cases of HS including postsplenectomy cases and shows no overlap with IDA, TT, and AIHA.