title: Stability of eosin-5'-maleimide dye used in flow cytometric analysis for red cell membrane disorders.
abstract: BACKGROUND
  The eosin-5'-maleimide (EMA) binding test using flow cytometry is a common method to measure reduced mean channel fluorescence (MCF) of EMA-labeled red blood cells (RBCs) from patients with red cell membrane disorders. The basic principle of the EMA-RBC binding test involves the covalent binding of EMA to lysine-430 on the first extracellular loop of band 3 protein.
  
  
  METHODS
  In the present study, the MCF of EMA was analyzed for samples derived from 12 healthy volunteers (controls) to determine the stability (i.e., the percentage decrease in fluorescence) of EMA over a period of 1 year.
  
  
  RESULTS
  Comparison of periodical MCF readings over time, that is, at 2-month intervals, showed that there were no significant changes in mean channel fluorescence for up to 6 months; however, there was a significant decrease in MCF at 8 months.
  
  
  CONCLUSIONS
  For optimal dye utilization, EMA remained stable only for up to 6 months. Therefore, we recommend reconstitution of the dye every 6 months when implementing this test and storage at -80℃ in dark conditions.
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Simmi
authors.initials: S
authors.lastname: Mehra
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Neetu
authors.initials: N
authors.lastname: Tyagi
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Pranav
authors.initials: P
authors.lastname: Dorwal
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Pande
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Dharmendra
authors.initials: D
authors.lastname: Jain
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Sachdev
authors.affiliation: Department of Pathology, Medanta, The Medicity, Gurgaon, India.
authors.forename: Vimarsh
authors.initials: V
authors.lastname: Raina
keywords: Flow Cytometry; Hereditary spherocytosis; Red Blood cells