In vitro replication of relationship between α1-microglobulin reduction rate and albumin leakage in post-dilution hemodiafiltration.

Efficient removal of middle-to-large molecules, such as α1-microglobulin (α1-MG, 33 kDa), is essential for mitigating long-term complications in patients undergoing hemodiafiltration (HDF). However, objective evaluation of diafilter performance requires standardized laboratory systems that can reproduce clinical transport characteristics while monitoring albumin leakage. This study established an in vitro experimental system utilizing recombinant α1-MG to evaluate post-dilution on-line HDF. Two configurations were compared: Circuit#1, featuring an auxiliary pump at the blood outlet, and Circuit#2, where the pump was removed to optimize flow regulation. Results demonstrated that Circuit#1 significantly deviated from clinical benchmarks due to internal pressure accumulation. Conversely, Circuit#2 successfully mirrored clinical trends, showing a strong positive correlation between α1-MG removal and albumin leakage. Observed clearances in Circuit#2 were slightly higher than clinical averages, likely due to the smaller molecular weight of the recombinant solute (31 vs. 33 kDa), reduced circulation volume, and the absence of α1 in vitro-MG-IgA dimer binding complexes. This validated model provides a robust and reliable platform for the standardized assessment and development of next-generation blood purification devices.