Plasma Separation Efficiency in Double Filtration Plasmapheresis: A Retrospective Study of Patients With Hyperlipidemia

ABSTRACT Background Double filtration plasmapheresis (DFPP) is a membrane‐based apheresis technique that separates plasma components using two sequential filters; it is commonly used to remove high‐molecular‐weight substances across various indications. While various metrics such as “plasma removal efficiency” are well established in therapeutic plasma exchange, “plasma separation efficiency” (PSE) remains unreported in DFPP. This study aims to evaluate PSE across DFPP sessions performed with plasma filters of different pore sizes. Materials and Methods A retrospective study of DFPP procedures performed in patients with hyperlipidemia at a single center between April and July 2025 was conducted. Patient demographics, laboratory values, and procedural parameters were collected. PSE was calculated with and without hematocrit (HCT) adjustment (PSE 1 and PSE 2 ). Associations with procedural variables were assessed using paired tests and multivariate linear regression. Results A total of 42 DFPPs were performed in 19 patients using the Inuspheresis system, alternating two plasma fractionators (DFPP‐1 and DFPP‐2 with large and small pore size, respectively). PSE 2 and PSE 1 declined significantly from DFPP‐1 to DFPP‐2 ( p = 0.0002 and p = 0.0014, respectively), with Cohen's d indicating large and moderate‐to‐large effect sizes. DFPP also resulted in significant reductions in total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, lipoprotein(a), and C‐reactive protein. Multivariate models showed that the plasma separation rate and HCT shifts were significantly associated with PSE 2 and PSE 1 during DFPP‐2 but not during DFPP‐1. Conclusions PSE is a reproducible parameter influenced by membrane pore size and procedural factors. Incorporating PSE monitoring, particularly with HCT adjustment, may support optimization of individualized DFPP protocols in routine apheresis practice.