TITLE:
Using Medium Cut-Off Membranes in Online Hemodiafiltration: Results and Considerations
AUTHORS:
Konstantinos S. Mavromatidis, Irini M. Kalogiannidou, Emine S. Impis, Alexandros M. Atalla, Pelagia A. Kriki, Gkiounai S. Katzel Achmet
KEYWORDS:
Medium Cut-Off, Hemodiafiltration, Predilution, Postdilution, Expanded Hemodialysis, Conventional Hemodialysis, Kt/V, URR, β2-Microglobulin, Prolactin
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.14 No.4,
April
20,
2026
ABSTRACT: Aim: Medium cut-off membranes are not used in hemodiafiltration methods because they are considered to lose large amounts of albumin and there is a potential risk to patients. This study was designed to determine whether the use of medium cut-off membranes in online hemodiafiltration (post- and pre-dilution) was safe, and to what extent do patients benefit when using online hemodiafiltration with these filters in terms of medium molecular weight toxins. Patients Methods: Fifteen patients (7F, 8M), median age 71 years, who had been on dialysis for 17 - 486 months, were randomly enrolled. They were scheduled to undergo predilution online hemodiafiltration (Group A), postdilution (Group B), and expanded hemodialysis (Group C) sessions with the same medium cut-off dialyzer and a session conventional hemodialysis with a low flux filter of the same surface area (Group D). Results: The Kt/V and urea reduction ratio of the Groups A and B were better than Groups C and D (but not in all comparisons). Specifically, Kt/V was better in Group B in comparison with Groups C and D. Also, urea reduction ratio of Group A was better than in Group D, and Group B was marginally better than Group D (p β2-microglobulin (in mg/session) and prolactin (% differences) in online hemodiafiltration (pre- or post-dilution) were better in comparison with other methods of dialysis assessed in this study (expanded or conventional hemodialysis). Only the comparison of removed amount of β2-microglobulin in postdilution online hemodiafiltration (Group B) and in expanded hemodialysis (Group C) shows a marginal significance of p value (p = 0.055). The amount of albumin lost (in g/session) (Table 3) was significantly higher with online hemodiafiltration (pre- or post-dilution) compared to both expanded hemodialysis and conventional hemodialysis. The largest albumin loss observed was 130.3 g/session in postdilution online hemodiafiltration. Also, in predilution online hemodiafiltration, 3 patients had zero albumin loss, while in postdilution, 2 had 0 albumin loss, in comparison to the expanded hemodialysis group of whom 7 losses ranged from 23.0 to 80.0 g/session. No clinical side effects (i.e. episodes of hypotension) were recorded in our patients during the study with any of the methods used. Conclusion: From the study it is concluded that the application of medium cut-off dialyzers provided higher clearance of toxins (small and medium molecular weight) with a toleration of albumin loss in postdilution online hemodiafiltration in comparison to the expanded hemodialysis. In relation to removing medium molecular weight toxins when cannot be applied postdilution online hemodiafiltration using the predilution hemodiafiltration, is a better choice than expanded hemodialysis for the best possible clearance provided, without side effects.