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

Abstract

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 OFTs in future.

Old and new insights into the diagnosis of hereditary spherocytosis

“…Attempts were made to combine flow cytometric assessment with the classic osmotic fragility test (34); however, this proved to be a laborious and time-consuming method which did not gain a foothold. The flow cytometric osmotic fragility (FCOF) test has very high sensitivity and specificity for detecting HS (33,(35)(36)(37)(38). Moreover, Shim and Won found that the result of the FCOF test is correlated with the clinical severity of the disease (39).…”

Eosin‐5’‐maleimide binding test—Do we use appropriate reference values to detect hereditary spherocytosis in neonates?

“…Surprisingly, we found that the increased cut‐off value at which we diagnosed HS with the highest probability is definitely higher than is applied for older patients. It is even higher than the highest values found in the worldwide literature (79%‐89%) . Applying a higher cut‐off value will contribute to a decrease in the test's specificity—it will result in a higher number of falsely positive results.…”

“…It is more suitable to express EMA test results in percentage of fluorescence of control cells rather than mean fluorescence intensity, since different values of its intensity can be obtained using different flow cytometers or even samples of a dye prepared for staining. The cut‐off value for an EMA test to diagnose HS differs between laboratories and studied populations . Many studies do not include newborns to analyse EMA test specificity and sensitivity.…”

Advances in understanding the pathogenesis of red cell membrane disorders

“…The flow‐cytometric osmotic fragility test is a new method for the diagnosis of HS, HE and DHS in combination with eosin‐5'‐maleimide testing. It is based on the assessment of the proportion of residual RBCs after the induction of haemolysis with a hypotonic solution (Utsugisawa et al , ; Arora et al , ; Ciepiela et al , ). Recently, a new method for the differential diagnosis of RBC membrane defects based on a label‐free optical marker has been devised (Mugnano et al , ).…”