What Is the Difference between Post- and Pre-Dilution in On-Line Haemodiafiltration in the Removing of Median-Molecular-Weight Toxins?

Abstract

Introduction: β 2 -microglobulin and prolactin are medium-molecular-weight toxins. We believe that the rate of removal of these molecules, using filters with two different surfaces, in post-and pre-dilution haemodiafiltration, will be of interest to the literature. Methods: We studied, in 12 haemodialyzed patients, the removal of those, with filter with surface of 2.5 m 2 (Group A) or 2.1 m 2 (Group B) with post-dilution haemodiafiltration, and with a filter with surface 2.5 m 2 with pre-dilution (Group C). Results: Satisfactory removal of β 2 -microglobulin (best with post-dilution) was found, and a good rate of removal of prolactin without the filter surface played a role in both cases. Conclusion: The elimination of β 2 -microglobulin in post-dilution is not affected by the filter surface area. Pre-dilution achieves removal of β 2 -microglobulin, less than that of post-dilution. Prolactin was removed satisfactorily regardless of the filter surface in post-dilution, and its removal appears to be less than that of β 2 -microglobulin.