Lindgren A, et al. - Researchers performed this prospective controlled single-center cross-over study to compare reduction ratios (RRs) of molecules with different molecular weights (0.06– 150 kDa) during dialysis with medium cutoff (MCO) dialyzer [used in HD (hemodialysis)-mode] vs online-hemodiafiltration (ol-HDF) treatment with a conventional high-flux dialyzer. A total of 16 patients in Malmö, Sweden, participated. All patients had ongoing post-dilution ol-HDF treatment prior to the study. Findings demonstrated comparable RRs for ol-HDF and MCO-HD. For HDF vs MCO, a slightly higher RR of cystatin C (a small middle molecule) was detected but there was no difference in other measured molecules.