Dialysis water quality in the United States is governed by two things that facilities often conflate. The first is what CMS enforces. The second is what the current consensus standards require. They are not the same, and the gap between them matters.

The CMS compliance floor: ANSI/AAMI RD52:2004

CMS incorporates ANSI/AAMI RD52:2004, "Dialysate for Hemodialysis," by reference at 42 CFR 494.40. This is the standard dialysis facilities are surveyed against for Medicare and Medicaid participation. It sets the water and dialysate quality requirements a facility must meet to remain in compliance.

The current consensus standard: the ANSI/AAMI/ISO 23500 series (2024)

The consensus standards community has moved beyond the older RD documents. The ANSI/AAMI/ISO 23500 series — most recently revised in 2024 — is the current standard of care for dialysis water and fluid. It consolidated and replaced the earlier standards: Part 2 covers water treatment equipment (replacing the former RD62 equipment standard), Part 3 covers water for hemodialysis, and Part 5 covers the quality of dialysis fluid. The 2024 editions retain the established microbial and endotoxin limits and add refinements including recognition of recombinant Factor C for endotoxin testing.

A facility can meet the CMS-enforced RD52:2004 floor and still fall short of the tighter, current ISO 23500 consensus limits. Meeting the floor is mandatory; meeting the current consensus standard is where patient safety and best practice actually live.

How D and D Laboratory Supports Compliance

D and D Laboratory helps dialysis facilities test to both the CMS-enforced requirements and the current ISO 23500 series. Our ISO/IEC 17025-accredited testing covers endotoxin, microbial counts, trace metals, and the full chemical panel these standards require, with customized sample-collection kits, detailed reporting, and expert consultation.