Clinical Commentary Single-Use versus Reusable Dialyzers: The Known Unknowns Ashish Upadhyay, Marie Anne Sosa, and Bertrand L. Jaber Department of Medicine, Tufts University School of Medicine, and Department of Medicine, Division of Nephrology, Caritas St. Elizabeth’s Medical Center, Boston, Massachusetts The practice of reusing dialyzers has been widespread in the United States for decades, with single use showing signs of resurgence in recent years. Reprocessing of dialyzers has traditionally been acknowledged to improve blood–membrane biocompatibility and prevent first-use syndromes. These proposed advantages of reuse have been offset by the introduction of more biocompatible membranes and favorable sterilization techniques. Moreover, reuse is associated with increased health hazard from germicide exposure and disposal. Some observational studies have also pointed to an increased mortality risk with dialyzer reuse, and the potential for legal liability is another concern. The desire to save cost is the major driving force behind the continued practice of dialyzer reuse in the United States. It is imperative that future research focus on the environmental consequences of dialysis, including the need for more optimal management of disinfectant-related waste with reuse, and solid waste with single use. The dialysis community has a responsibility to explore ways to mitigate environmental consequences before single-use and a more frequent dialysis regimen becomes a standard practice in the United States. Clin J Am Soc Nephrol 2: 1079-1086, 2007. doi: 10.2215/CJN.01040207 D ialyzer reuse has been practiced in the United States for decades but remains a topic of ongoing contro- versy. Several large observational studies of variable quality have compared single-use with reused dialyzers, and some have demonstrated an increased mortality risk with reuse of dialyzers. However, it is generally accepted that reuse can be done safely when performed according to the standards set by the Association for the Advancement of Medical Instrumenta- tion (AAMI) (1). Full compliance in a practical setting, however, is difficult to attain, and rigorous quality control standards are vulnerable to poor implementation. This review summarizes the advantages and disadvantages of both dialyzer practices, namely reuse and single use, and provides guidance for future research directions. Dialyzer Reuse Rationale for Dialyzer Reuse Dialyzer reuse has historically been practiced in light of perceived potential benefits for the dialysis provider and the patient. The three major advantages for the provider include an economic benefit; the ability to use high-flux dialyzers, which traditionally have been more expensive; and a favorable envi- ronmental impact as a result of decreased generation of bio- medical waste. In light of declining and more restrictive Medi- care coverage for hemodialysis treatments, economic considerations are believed to be the driving force for contin- ued use of dialyzer reuse methods in the United States. The availability of cheaper high-flux dialyzers for single use means that the traditional benefit of the ability to reuse such dialyzers no longer holds true. From the patient’s standpoint, the con- ventional argument for reprocessing of dialyzers is to improve blood–membrane biocompatibility, particularly that of cellu- lose membranes, and the prevention of first-use syndromes usually associated with the use of ethylene oxide–sterilized dialyzers. In recent years, however, substituted cellulose and synthetic membranes have become the standard of care and have been promoted by published clinical guidelines for hemo- dialysis adequacy (2), and alternative sterilization methods are slowly replacing ethylene oxide. Dialyzer Reuse Trend in the United States The proportion of dialysis centers that reuse dialyzers in the United States increased steadily from the early 1980s, peaking in 1997. Indeed, data collected during the period of 1976 to 2002 by the Centers for Disease Control and Prevention (CDC) re- veal that approximately 20% of centers reused dialyzers in 1976, increasing to 80% in 1997, and subsequently declining to approximately 60% in 2002 (3). This trend has further declined in recent years as a result of the change in practice pattern favoring single use in some dialysis provider chains. Experts have estimated that as of 2005, approximately 40% of dialysis centers were likely to be reusing dialyzers (4). Methods for dialyzer reprocessing in US dialysis centers have also markedly evolved in the last 25 years (3). Indeed, the percentage of centers that used formaldehyde decreased from 94 to 20% between 1983 and 2002. During the same period, the proportion of centers that used peracetic acid increased from 5 Published online ahead of print. Publication date available at www.cjasn.org. A.U. and M.A.S. contributed equally to this work. Address correspondence to: Dr. Bertrand L. Jaber, Caritas St. Elizabeth’s Medical Center, 736 Cambridge Street, Boston, MA 02135. Phone: 617-562-7832; Fax: 617-562-7797; E-mail: bertrand.jaber@caritaschristi.org Copyright © 2007 by the American Society of Nephrology ISSN: 1555-9041/205–1079