AbstractRadiographic contrast media can lead to drastic changes of the morphology of erythrocytes. The change of the erythrocyte morphology is associated with a decreased deformability possibly resulting from distinctions in the loss of constituents of the membrane cytoskeleton. However, it is unclear whether there is an intravascular hemolysis as a consequence of the disintegration of the erythrocyte membrane. The results of this study showed, that free haemoglobin increased from 16.8 ± 10.0 mg/dl to 21.6 ± 12.6 mg/dl after Iopromide application (p = 0.240), while it slightly decreased from 20.5 ± 10.3 mg/dl to 19.5 ± 12.2 mg/dl after Iodixanol application (p = 0.547). The slight decrease of free haemoglobin after application of Iodixanol differed significantly compared to the increase of free haemoglobin after Iopromide application (p < 0.05). This different response is thought to give evidence to the assumption that the erythrocyte membrane integrity was compromised leading to the release of free haemoglobin as an indicator of hemolysis as well.