Hence, the question arises whether high convection volumes are achievable in the majority of patients. In a previous sub-analysis of CONTRAST, it was found that the most important determinants of achieved convection volume were treatment time and blood flow rate. Moreover, it was noted that convection volumes and filtration fraction (defined as the ratio of extracted plasma water flow rate to blood flow rate) differed markedly per participating center, suggesting different practice patterns. Thus, it is plausible that the optimization of these apparently seemingly modifiable factors, on an individual basis through a dedicated standardized protocol, could translate into a higher achieved convection volume.