In the Renal Replacement bracket we see all the usual players, except for convective clearance, which is not in mainstream use in chronic dialysis units in the US. It is relatively unknown this side of the Atlantic (west of!) but online hemodiafiltration (olHDF) is used in many parts of Europe. olHDF utilizes diffusive clearance and convective clearance during a regular dialysis session. To use convective clearance or hemofiltration a different machine is required and also a large volume of ultrapure water is needed. This large volume of water is made and stored centrally in a dialysis unit and then put ‘online’ and delivered to all the machines in a unit. There of course is a financial outlay in setting up a unit to provide olHDF but after that the cost difference is a matter of a few dollars per treatment (or euros) difference (anecdotal evidence). Our understanding of the middle molecule clearance using convective clearance would suggest olHDF should provide our patients better dialysis. Also, recent trials have suggested better outcomes vs standard hemodialysis but there was difficulty delivering high volumes of replacement fluid for each treatment session in some of these trials. See Paul’s RFN post. This team is a new treatment that can potentially improve outcomes for our dialysis patients. For this reason convective clearance reaches the final four for me.