Evaluation of OSMOCELLS, a new semi-automatic device for osmotic fragility assessment

Introduction: The osmotic fragility (OF) test was a central test for the diagnosis of hereditary red blood cell (RBC) disorders (mostly hereditary spherocytosis (HS), but thalassaemia as well). Nowadays although the traditional multitubes method has lost a prominent place, many laboratories still perform such a laboured test, despite the lack of standardization. In fact, the evaluation of OF may offer an inexpensive screening for RBC disorders. We present a new semi-automatic device, allowing the continuous recording of OF, by an updated dialysis method. Methods: Repeatability, stability over time, influence of the anticoagulant were evaluated among a population of healthy blood donors. The test was then performed among patients presenting inherited RBC disorders (HS or haemoglobinopathies) where OF is typically altered. Results: Repeatability was excellent; the parameters were greatly influenced by the nature of the anticoagulant and interestingly appeared stable for 48h. Patients with RBC disorders displayed the expected profile in regard with their disease: patients with HS all presented an increased OF while patients with haemoglobinopathy displayed resistant profiles. Conclusion: The device offers a substantial improvement in terms of standardization and consistency of the results and may offer a considerable gain for general laboratories.