‘Healthy’ and ‘Sick’ RBCs do not show the same behavior in the blood flow due to a significant difference in the membrane stiffness. When a RBC loses its natural state property, it will be come stiffer, i.e., its stretching and bending coefficients become very large compared to their counterparts in the natural state. Under such conditions, very large Lagrangian forces are created in the immersed boundary and it shows a very small degree of flexibility while moving with the flow.