Flow cytometric osmotic fragility test and eosin‐5’‐maleimide dye‐binding tests are better than conventional osmotic fragility tests for the diagnosis of hereditary spherocytosis

摘要

Abstract Introduction Hereditary spherocytosis ( HS ) is the most common inherited hemolytic anemia with heterogeneous clinico‐laboratory manifestations. We evaluated the flow‐cytometric tests: eosin‐5’‐maleimide ( EMA ) and flow‐cytometric osmotic fragility test ( FOFT ) and the conventional osmotic fragility tests ( OFT ) for the diagnosis of hereditary spherocytosis ( HS ). Methods One hundred two suspected HS patients underwent EMA , FOFT , incubated OFT ( IOFT ), and room temperature OFT ( RT ‐ OFT ). In addition, 10 cases of immune hemolytic anemia ( IHA ) were included, and performance of the above 4 tests was evaluated. For EMA and FOFT , 5 normal controls were assessed together with the patients and cutoffs were calculated using receiver‐operator‐characteristics curve ( ROC ) analysis. Results The best cutoff for % EMA decrease was 12.5%, and for FOFT , %residual red cells (% RRC ) was 25.6%. The sensitivity and specificity of RT ‐ OFT was 62.06% and 86.3%, respectively, while that of IOFT was 79.31% and 87.67%, respectively. Both flow cytometric tests performed better. Sensitivity and specificity of EMA was 86.2% and 93.9% respectively, and that of FOFT was 96.6% and 98.63%, respectively. The combination of the FOFT with IOFT or EMA dye‐binding test yields a sensitivity of 100%, but with EMA , it had a higher specificity. Hb/ MCHC was a predictor of the severity of the disease while % EMA decrease and % RRC did not correlate with severity of the disease. Conclusion Flow‐cytometric osmotic fragility test is the best possible single test followed by EMA for diagnosis of HS . A combination of FOFT and EMA can correctly diagnose 100% patients. These tests are likely to replace conventional OFT s in future.