Flow cytometric analysis of patients with hereditary spherocytosis–an Indian scenario

Abstract

Objectives: Flow cytometry osmotic fragility test (FC-OFT) was a recently introduced screening test for hereditary spherocytosis (HS). This study was conducted to evaluate the utility of FC-OFT in all newly diagnosed cases of HS, to compare its diagnostic value with conventional OFT and to correlate with clinical disease severity. Methods: In this study, the percentage of residual red cells (%RRC) was measured using flow cytometer after creating a red cell suspension. Subsequently, this was spiked with deionized water for FC-OFT in all cases of HS (n = 40), healthy subjects (n = 40) and beta-thalassemia traits (BTT) (n = 20). Results: The receiver operator curve analysis defined the optimal cut-offs for FC-OFT-derived indices, such as %RRC value (≤16.29%) and %RRC ratio (>1.72), for HS cases when compared with healthy subjects and BTT (p < 0.05). The FC-OFT (96%) achieved higher test efficiency than the conventional OF test (68.9%). A significant positive and a negative correlation were found between number of spherocytes/hpf and %RRC ratio (p = 0.001) and %RRC values (p = 0.0486). No significant correlation was observed between %RRC value (p = 0.8934), %RRC ratio (p = 0.6348) and HS disease severity score. Conclusion: Our results suggest that FC-OFT could be the better screening test for HS cases in developing countries if flow cytometer is available.