Flow cytometric detection of erythrocyte osmotic fragility.
BACKGROUND
Hereditary spherocytosis (HS) is the most common cause of inherited chronic hemolysis. The various tests developed for HS screening have many shortcomings. The purpose of this study was to develop a new, simple, reliable test using flow cytometry.


METHODS
In this new test, deionized water, a hemolysis-inducing agent, is spiked to a red cell suspension during acquisition, and the count of red cells is measured sequentially in real-time using flow cytometry. In this study, the optimal parameters for this test were established, and the discriminatory power of the adopted protocol was verified among several groups with various degrees of osmotic fragility (OF).


RESULTS
The established protocol successfully discriminated between blood analyzed immediately and blood stored for 24 h (P < 0.00001). With healthy individuals as a reference, the OF measured by this protocol was significantly decreased in patients with iron deficiency anemia (P = 0.030) and was significantly increased in HS patients (P = 1.1 x 10(-9)). This new test found all 11 HS patients to have increased OF.


CONCLUSIONS
This new test was verified to be simple, quantitative, objective, and cost-effective for the measurement of OF. We suggest this test as another effective approach for HS screening, although its assay performance will require further verification through more clinical trials.
Won
Dong Il
DI
Department of Clinical Pathology, Kyungpook National University School of Medicine, Daegu, Republic of Korea. wondi@knu.ac.kr
Suh
Jang Soo
JS
D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004912:Erythrocytes / Q000187:drug effects / Q000473:pathology* / Q000502:physiology; D004913:Erythrocytes, Abnormal / Q000473:pathology / Q000502:physiology; D005260:Female; D005434:Flow Cytometry / Q000191:economics / Q000379:methods*; D006461:Hemolysis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009996:Osmotic Fragility / Q000187:drug effects / Q000502:physiology*; D009997:Osmotic Pressure / Q000187:drug effects / Q000502:physiology; D011237:Predictive Value of Tests; D013103:Spherocytosis, Hereditary / Q000097:blood / Q000175:diagnosis*