Evolving Dialysis Water and Fluid Quality Standards in Portugal

Abstract

Dialysis water and dialysis fluid quality have evolved from operational concerns into central components of hemodialysis safety, quality management and service resilience. Early experience showed that water considered safe for drinking could still expose hemodialysis patients to clinically relevant chemical and microbiological hazards, owing to the large volumes of dialysis fluid used, the semipermeable interface with blood, and patients' limited renal capacity to eliminate contaminants. In Portugal, this evolution was shaped by early regulatory milestones, including Decreto-Lei n. 392/93, and by successive editions of the Manual de Boas Praticas, from the first Manual de Boas Praticas de Hemodiálise in 2001 to the 2011 and 2017 editions of the Manual de Boas Praticas de Diálise Crónica. The 2025 edition, officially released in 2026, marks a further step in this pathway, adopting a modular structure and updating guidance on hemodialysis water treatment systems, dialysis water, dialysis fluids, and sustainability. This article places the 2025 revision in historical context and analyses its alignment with the ISO 23500 series, focusing on terminology, chemical and microbiological quality requirements, ultrapure dialysis fluid, online-produced substitution fluid, validation, surveillance, documentation and responsibilities. The revised Manual supports a more integrated approach in which patient safety depends on the full quality chain, from incoming water and water treatment infrastructure to concentrates and final dialysis fluid, with additional validated safeguards for ultrapure dialysis fluid and online-produced substitution fluid when required by the prescribed treatment modality. In the context of climate change, water scarcity, and increasing variability in feed-water quality, efficient, safe, and resilient water treatment systems are essential. Sustainability must therefore be integrated into dialysis practice without compromising chemical or microbiological safety.