Refinement of Replacement Fluid Using Human Serum Albumin Preparation to Enhance Biocompatibility in Therapeutic Plasma Exchange

Human serum albumin (HSA) solution is widely used as a replacement fluid during therapeutic plasma exchange (TPE). However, the ionic concentrations in commercially available 5% HSA solutions differ significantly from physiological levels. In this study, we developed a simple method for preparing a replacement fluid with ion concentrations closer to physiological norms by mixing 25% HSA with lactated Ringer's solution, sodium chloride, and calcium gluconate hydrate. We prepared three types of replacement fluids, each with a 4.0% albumin concentration and total volumes of 1.83, 2.43, and 3.04 L, and confirmed their compositional stability for up to 48 h. Compared with the standard 5% HSA solution, the prepared fluids had calcium, sodium, potassium, and chloride levels more closely aligned with physiological values. Using HSA‐based replacement fluids with preadjusted electrolyte concentrations may help reduce the risk of imbalances, such as hypocalcemia, during TPE.