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.