Delayed Measurement of Eosin-5′-Maleimide Binding May Affect the Test Results of Highly Hemolyzed Samples In Vivo and In Vitro—A Case Study

Abstract

Diagnosis of hereditary spherocytosis (HS) is based on clinical evaluation and eosin-5'-maleimide (EMA) test. A decrease in EMA fluorescence compared with healthy individuals is typical for HS and serves as a basis for HS diagnosis. Sensitivity and specificity of the test is high and false-positive results rarely occur. Studies have shown that anticoagulated blood sample when stored at 4°C for 7 days do not affect the test results. This case study is about an autoimmune hemolytic anemia patient who showed a primary positive result for EMA test (decrease in EMA fluorescence-47% compared with 100% for samples of healthy individual), when the test was performed in the sample stored for 48 hours after venipuncture and before staining. An irrelevant decrease (92.5% compared with 100% for samples of healthy individual) was found when freshly collected sample was analyzed. On the basis of the results obtained, it is recommended that EMA staining should be performed on the same day of blood collection for patients with significant hemolysis.

Integrative preimplantation genetic testing analysis for a Chinese family with hereditary spherocytosis caused by a novel splicing variant of SPTB

“…The laboratory diagnosis of HS mainly relies on red blood cell (RBC) morphology examination, osmotic fragility (OF) test, acidized glycerolysis test (AGLT), and maleimide eosin (EMA) ( Farias, 2017 ). Although the EMA test showed maximum disease specificity, no single test can identify all cases of hereditary spherocytosis ( Bianchi et al, 2012 ; Ciepiela et al, 2016 ). At present, molecular tests based on next-generation sequencing technology are widely used in the differential diagnosis and confirmation of pathogenic variants, further improving the accuracy and specificity of the diagnosis of HS ( Xue et al, 2019 ; Richmond et al, 2020 ; Xue et al, 2020 ; Fan et al, 2021 ; Xie et al, 2021 ).…”