Density-based separation in multiphase systems provides a simple method to identify sickle cell disease

Significance Red blood cells with a high density (ρ > 1.120 g/cm 3 ) are characteristic of sickle cell disease. This paper demonstrates a density-based separation of red blood cells in a system of aqueous multiphase polymers that enables a visual test that identifies sickle cell disease, starting from samples of whole blood, in less than 12 min. This low-cost, simple test could provide a means to enable diagnosis of sickle cell disease in low-resource settings and enable life-saving interventions for children with the disease. The method itself provides a demonstration of the use of a biophysical indicator (here, density) rather than a biochemical marker (e.g., proteins separated by gel electrophoresis) as a means to do point-of-care hematology.