Dialysis — hemodialysis in particular — requires direct, prolonged exposure of a patient’s bloodstream to purified water. Hemodialysis patients typically undergo three sessions per week, each lasting 3–5 hours, during which 120–180 liters of dialysis fluid contacts their blood across a semi-permeable membrane. The water quality requirements for dialysis are among the most stringent in any medical application — and PFAS contamination presents a unique and serious risk to this vulnerable population.
Why Dialysis Patients Face Elevated PFAS Risk
Healthy kidneys eliminate some PFAS from the body through urine, though the process is slow and incomplete (explaining the long serum half-lives of many PFAS compounds). For patients with end-stage renal disease (ESRD) on dialysis, this elimination pathway is essentially absent. Any PFAS that enters the body — through food, water, or air — has no renal clearance mechanism.
While dialysis removes some waste products from blood, conventional hemodialysis is not designed to remove PFAS. Studies have found that PFAS are poorly cleared during hemodialysis sessions, meaning dialysis patients can accumulate PFAS in serum at rates comparable to or potentially exceeding those of the general population.
More concerning, dialysis fluid — which contacts blood across the dialyzer membrane — is made from the local water supply (highly purified but potentially PFAS-contaminated). Any PFAS in the water supply could potentially transfer to the patient’s bloodstream during treatment.
Water Purification Standards for Dialysis
The Association for the Advancement of Medical Instrumentation (AAMI) and the International Organization for Standardization (ISO 23500 series) establish water quality standards for dialysis. These standards specify limits for microbial contamination, endotoxins, and chemical contaminants — but historically did not specifically address PFAS.
Current AAMI standards require that dialysis facilities conduct chemical analysis of source water using a comprehensive panel including heavy metals, inorganic ions, and certain organics. As awareness of PFAS contamination has grown, some dialysis accreditation programs have begun recommending or requiring PFAS testing.
Treatment Technologies in Dialysis Water Systems
Dialysis water treatment systems are already among the most sophisticated water purification installations outside of pharmaceutical manufacturing. A typical system includes:
- Depth filtration and softening
- Activated carbon adsorption (for chlorine, chloramines, and organic removal)
- Reverse osmosis — the primary purification stage
- Deionization as a polishing step
- Ultraviolet disinfection
- Ultrafiltration as a final barrier
The RO stage in a properly functioning dialysis water system should provide 90–99% PFAS rejection, substantially reducing — though potentially not eliminating — PFAS from dialysis fluid. However, RO membrane condition, system bypasses, and other operational factors can affect actual performance.
Recommendations for Dialysis Facilities
Dialysis facilities in areas with known or suspected PFAS water contamination should:
- Test source water for PFAS using EPA Methods 533 and 537.1 through a certified laboratory
- Verify RO system performance through product water testing
- Implement enhanced monitoring if source water PFAS levels are detectable
- Consult with their water system manufacturer regarding PFAS-specific performance data for their installed membranes
- Consider adding granular activated carbon pre-treatment if RO alone is insufficient
Patient Considerations
Dialysis patients concerned about PFAS exposure should discuss this issue with their nephrologist and the dialysis facility’s water quality officer. Patients can also take steps to reduce non-dialysis PFAS exposure through filtered drinking and cooking water at home — particularly important given the absence of renal PFAS elimination in this population. A high-quality reverse osmosis filter for home drinking water is especially valuable for dialysis patients as part of a comprehensive exposure reduction strategy.