ANSI/AAMI 23500 – Guidance for the preparation and quality management of fluids for hemodialysis and related therapies

This AAMI Standard (a revision of RD52) provides guidance for dialysis practitioners or providers on the preparation of dialysis fluids for hemodialysis and related therapies.  It includes total management of water treatment equipment, concentrate powders to liquid, and the preparation of final dialysis fluids.  But it excludes sorbent-based dialysis fluid regeneration systems, prepackaged solutions for continuous renal replacement therapy, and solutions for peritoneal dialysis.

The quality requirements for dialysis water all refer to the latest 13959 Standard.  Requirements for concentrate solutions and systems point back to 13958 and the water used for preparation ties back to 13959, whereas the dialysis fluid quality itself is found in Standard 11663.  Requirements for dialysis fluid collected as close to the inlet of the dialyzer is as follows:

Microbiological Level Standard Dialysis Fluid
Maximum Allowable Level Action Level
Colony Forming Units < 100 CFU/mL ≥ 50 CFU/mL
Endotoxin Units < 0.50 EU/mL ≥0.25 EU/mL


In conjunction with dialysis fluid quality, this latest Standard provides a US deviation to ISO 23500:2014.  It allows for an additional cultivation medium with different incubation temperature and time.

Cultivation medium Incubation temperature Incubation time
Trypticase soy agar (TSA, a soybean casein digest agar) or standards method agar and plate count agar (also known as TGYE) 35 °C 48 h


The Standard emphasizes understanding the critical aspect and intricate nature of producing dialysis fluid from a potable water tap.  It points to Standard 26722 for water system guidance, but also mentions the user’s responsibility when not dealing with a single fluid system supplier. Microbiological aspects are also reviewed as critical for successful system operation.  Two sections are designed to assist the providers with validation techniques and quality management directives in order to establish a safe, predictable, and reliable working system.

It also covers ongoing monitoring of dialysis water, dialysis fluid, concentrates quality, and installed water treatment devices.  Detailed instructions for monitoring water treatment equipment is written out, but is also found in reference charts located in Annex C.  It includes, but not limited to, sediment filters, water softeners, carbon filters, reverse osmosis (RO) machines, deionization (DI) systems, water storage tanks, distribution systems, ultraviolet (UV) units, ozone generators, and hot water disinfection systems.  It also includes concentrate systems as it relates to mix and delivery, additives, and fluid proportioning.

To comply with water and dialysis fluid requirements, disinfection strategies should be designed to prevent microbial proliferation with testing to indicate effectiveness. Proactive strategies should be established from system start-up so as to prevent biofilm formation.  Disinfection frequency should follow manufacturer’s recommendations as long as routine monitoring meets requirements.  Monitoring methods that include frequency, proper sample collection, heterotrophic plate counts, and bacterial endotoxin tests are critical for monitoring strategies.  Part of that is also creating a suitable work environment where items are labeled, information is accessible, personnel are trained, and documented policies and procedures are clearly understood.

Finally, there are several Annex sections that explain rationale for the development and the provision of the Standard itself, for water treatment equipment, for monitoring guidelines, for microbial control strategies, and for validation practices.  This Standard also includes informative sections designated specifically for both home and acute hemodialysis.

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