ISO 23500-5:2024

Overview

ISO 23500-5:2024 - Preparation and quality management of fluids for haemodialysis and related therapies - Part 5: Quality of dialysis fluid for haemodialysis and related therapies defines minimum chemical and microbiological quality requirements for dialysis fluids. It covers dialysis fluid used in haemodialysis and haemodiafiltration and online-produced substitution fluid based on dialysis fluid. The standard complements ISO 23500-3 (water) and ISO 23500-4 (concentrates) and interfaces with equipment safety and monitoring requirements in IEC 60601-2-16.

Key topics and requirements

• Microbiological quality
  • Standard dialysis fluid: total viable microbial count < 100 CFU/ml and endotoxin < 0.5 EU/ml.
  • Ultrapure dialysis fluid: total viable microbial count < 0.1 CFU/ml and endotoxin < 0.03 EU/ml.
  • Action levels: recommended (typically ~50% of maximum allowable) to trigger corrective measures such as disinfection and retesting.
  • Online substitution fluid: must be sterile and nonpyrogenic; production systems (e.g., ultrafiltration with validated bacteria- and endotoxin-retentive filters) require validation and ongoing surveillance.
• Chemical composition and contaminants
  • Dialysis fluid shall be prepared from water and acid/bicarbonate concentrates that meet ISO 23500-3 and ISO 23500-4.
  • Delivery systems and materials must not leach chemical contaminants; trace element and heavy metal limits (referenced in Annex B) are specified.
• Testing and conformity
  • Guidance on sampling (e.g., aseptic capture at the dialyser inlet or sampling ports), microbiological culture methods, endotoxin testing (including updated alternatives), and chemical analyses are provided.
  • Where validated bacteria-/endotoxin-retentive filters are used and operated per manufacturer instructions, routine microbial testing may be waived unless specified by the manufacturer.

Practical applications

• Ensures patient safety by minimizing exposure to biological and chemical contaminants in dialysis fluid.
• Supports clinical protocols for routine surveillance, disinfection, and corrective actions in dialysis centers.
• Informs validation and commissioning of online substitution fluid systems for haemodiafiltration and haemofiltration.
• Guides laboratory testing strategies (microbiology, endotoxin, trace metals) and sampling procedures used by clinical labs and hospital quality teams.

Who uses this standard

• Nephrologists and physicians responsible for dialysis therapy
• Dialysis facility managers and infection-control teams
• Clinical engineers and biomedical technicians
• Medical device manufacturers of dialysis machines, filters and central delivery systems
• Regulatory and accreditation bodies

Related standards

• ISO 23500-1 - General requirements for preparation and quality management of dialysis fluids
• ISO 23500-3 - Quality of water for haemodialysis
• ISO 23500-4 - Concentrates for haemodialysis
• IEC 60601-2-16 - Safety/monitoring for haemodialysis equipment

Keywords: ISO 23500-5:2024, dialysis fluid quality, haemodialysis, ultrapure dialysis fluid, microbiological requirements, chemical contaminants, online substitution fluid, dialysis fluid testing.