Hemoadsorption/Hemodialysis: Rationale, Indications, and Practical Application.

Uremic toxicity extends beyond small solutes to include middle molecules and protein-bound uremic toxins (PBUTs), which are inadequately removed by conventional dialysis. These limitations arise from membrane-dependent transport mechanisms and the high-affinity binding of PBUTs to albumin, restricting their effective clearance. Hemoadsorption, when coupled with hemodialysis (HAHD), provides a complementary approach by enabling direct physicochemical interactions between circulating solutes and sorbent materials, thereby overcoming constraints related to molecular size and protein binding. The concept of residual uremic toxicity highlights the persistence of biologically active solutes despite optimized dialysis delivery. In this context, patient selection should follow a phenotype-based, toxin-domain approach. Four main phenotypes are proposed: inflammatory, PBUT-driven symptom, middle-molecule burden, and neurocognitive. Each phenotype reflects a dominant toxin profile and provides a rationale for targeted extracorporeal strategies beyond conventional adequacy metrics. HAHD should be considered in patients with persistent symptoms, inflammation, or biochemical abnormalities despite optimized therapy. Treatment prescription must be individualized, integrating frequency, duration, and blood flow to reduce cumulative toxin burden over time. Emerging evidence suggests that HAHD may improve inflammatory markers, patient-centered outcomes, and potentially survival. Overall, HAHD represents a phenotype-driven strategy to better align extracorporeal therapies with the complex biology of uremia.