Objectives: Current guidelines recommend the eosin-5'maleimide (EMA) binding test and cryohemolysis test for screening for hereditary spherocytosis (HS), and the flow cytometric osmotic fragility (FC OF) test was recently developed to replace the classic OF test. We evaluated the performance of the EMA binding test, FC OF test, cryohemolysis test, and the hemoglobin (Hb)/mean corpuscular hemoglobin concentration (MCHC) ratio in the diagnosis of HS and assessed whether these tests reflect the

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... nical severity of HS. Methods: A total of 153 patients with anemia (33 with HS, 40 with autoimmune hemolytic anemia, 40 with anemia of chronic disease, and 40 with iron deficiency anemia [IDA]) and 140 healthy controls were enrolled, and the performance of the three tests was evaluated. Results: Both the EMA binding test (area under the curve [AUC], 0.996) and the FC OF test (AUC, 0.992) performed satisfactorily, but the cryohemolysis test (AUC, 0.723) performed significantly worse because of false positivity in patients with IDA. The Hb/MCHC ratio (P < .001) was able to reflect the clinical severity of HS. Conclusions: Our results demonstrate that both the EMA binding and FC OF tests are useful as screening tests for the diagnosis of HS, but the cryohemolysis test has limited use due to its false positivity in IDA, with the Hb/MCHC ratio the most useful parameter for assessing the clinical severity of HS.