Latest ISO standard :Water for haemodialysis and related therapies

ISO 23500-3:2019

ISO 13959:2014(en)Water for haemodialysis and related therapies
This standard has been replaced by ISO 23500-3:2019

Introduction
Assurance of adequate water quality is one of the most important aspects of ensuring a safe and effective delivery of haemodialysis, haemodiafiltration, or haemofiltration.
This International Standard contains minimum requirements, chemical and microbiological, for the water to be used for preparation of dialysis fluids, concentrates, and for the reprocessing of haemodialysers and the necessary steps to ensure compliance with those requirements.
Haemodialysis and haemodiafiltration can expose the patient to more than 500 l of water per week across the semi-permeable membrane of the haemodialyser or haemodiafilter. Healthy individuals seldom have a weekly oral intake above 12 l. This over 40-fold increase in exposure requires control and monitoring of water quality to avoid excesses of known or suspected harmful substances. Since knowledge of potential injury from trace elements and contaminants of microbiological origin over long periods is still growing and techniques for treating drinking water are continuously developed, this International Standard will evolve and be refined accordingly. The physiological effects attributable to the presence of organic contaminants in dialysis water are important areas for research. At the time this International Standard was published it was not possible to specify threshold values for organic contaminants permitted in water used for the preparation of dialysis fluids, concentrates, and reprocessing of haemodialysers. The issue of organic contaminants will be reassessed on the next revision of this International Standard.
Within this International Standard, measurement techniques current at the time of publication have been cited. Other standard methods may be used, provided that such methods have been appropriately validated and compared to the cited methods.
The final dialysis fluid is produced from concentrates or salts manufactured, packaged, and labelled according to ISO 13958 mixed with water meeting the requirements of this International Standard. Operation of water treatment equipment and haemodialysis systems, including ongoing monitoring of the quality of water used to prepare dialysis fluids, and handling of concentrates and salts are the responsibility of the haemodialysis facility and are addressed in ISO 23500. Haemodialysis professionals make choices about the various applications (haemodialysis, haemodiafiltration, haemofiltration) and should understand the risks of each and the requirements for safety for fluids used for each.
The verbal forms used in this International Standard conform to usage described in Annex H of the ISO/IEC Directives, Part 2. For the purposes of this International Standard, the auxiliary verb
— “shall” means that compliance with a requirement or a test is mandatory for compliance with this International Standard,
— “should” means that compliance with a requirement or a test is recommended but is not mandatory for compliance with this International Standard, and
— “may” is used to describe a permissible way to achieve compliance with a requirement or test.
This International Standard is directed towards manufacturers and providers of water treatment systems and also to haemodialysis facilities.

Scope
This International Standard specifies minimum requirements for water to be used in haemodialysis and related therapies.
This International Standard includes water to be used in the preparation of concentrates, dialysis fluids for haemodialysis, haemodiafiltration and haemofiltration, and for the reprocessing of haemodialysers.
The operation of water treatment equipment and the final mixing of treated water with concentrates to produce dialysis fluid are excluded from this International Standard. Those operations are the sole responsibility of dialysis professionals. This International Standard does not apply to dialysis fluid regenerating systems.
2   Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
action level
concentration of a contaminant at which steps should be taken to interrupt the trend toward higher, unacceptable levels
2.2
chlorine, combined
chlorine that is chemically combined, such as in chloramine compounds
Note 1 to entry: There is no direct test for measuring combined chlorine, but it can be measured indirectly by measuring both total and free chlorine and calculating the difference.
2.3

chlorine, free
chlorine present in water as dissolved molecular chlorine (Cl), hypochlorous acid (HOCl), and hypochlorite ion (OCl−)
Note 1 to entry: The three forms of free chlorine exist in equilibrium.

2.4
chlorine, total
sum of free and combined chlorine
Note 1 to entry: Chlorine can exist in water as dissolved molecular chlorine, hypochlorous acid, and/or hypochlorite ion (free chlorine) or in chemically combined forms (combined chlorine). Where chloramine is used to disinfect water supplies, chloramine is usually the principal component of combined chlorine.

2.5
colony-forming unit
CFU
measure of bacterial or fungal cell numbers that theoretically arise from a single cell when grown on solid media
Note 1 to entry: Colonies can also form from groups of organisms when they occur in aggregates.
2.6
device
individual water purification unit, such as a softener, carbon bed, reverse osmosis unit, or deionizer
Note 1 to entry: This term is synonymous with the term “component” as used by the US Food and Drug Administration (see Reference [49]).
2.7
dialysis fluid
dialysate
dialysis solution
aqueous fluid containing electrolytes and, usually, buffer and glucose, which is intended to exchange solutes with blood during haemodialysis
Note 1 to entry: The term “dialysis fluid” is used throughout this International Standard to mean the fluid made from dialysis water and concentrates that is delivered to the dialyser by the dialysis fluid delivery system. Such phrases as “dialysate” or “dialysis solution” are used in place of dialysis fluid in some countries; however, that usage is discouraged to avoid confusion.
Note 2 to entry: The dialysis fluid entering the dialyser is referred to as “fresh dialysis fluid”, while the fluid leaving the dialyser is referred to as “spent dialysis fluid.”
Note 3 to entry: Dialysis fluid does not include prepackaged parenteral fluids used in some renal replacement therapies, such as haemodiafiltration and haemofiltration.
2.8
dialysis fluid deliver water
System device that prepares dialysis fluid online from dialysis water and concentrates or that stores and distributes premixed dialysis fluid, circulates the dialysis fluid through the dialyser, monitors the dialysis fluid for temperature, conductivity (or equivalent), pressure, flow and blood leaks, and prevents dialysis during disinfection or cleaning modes
Note 1 to entry: The term includes reservoirs, conduits, proportioning devices for the dialysis fluid, and monitors and associated alarms and controls assembled as a system for the purposes listed above.
Note 2 to entry: The dialysis fluid delivery system can be an integral part of the single-patient dialysis machine or a centralized preparation system which feeds multiple bedside monitoring systems.
Note 3 to entry: Dialysis fluid delivery systems are also known as proportioning systems and dialysis fluid supply systems.
2.9
dialysis water
water that has been treated to meet the requirements of this International Standard and which is suitable for use in haemodialysis applications, including the preparation of dialysis fluid, reprocessing of dialysers, preparation of concentrates, and preparation of substitution fluid for online convective therapies
2.10
disinfection
destruction of pathogenic and other kinds of microorganisms by thermal or chemical means
Note 1 to entry: Disinfection is a less lethal process than sterilization because it destroys most recognized pathogenic microorganisms but does not necessarily destroy all microbial forms.
2.11
endotoxin
major component of the outer cell wall of gram-negative bacteria
Note 1 to entry: Endotoxins are lipopolysaccharides, which consist of a polysaccharide chain covalently bound to lipid A. Endotoxins can acutely activate both humoral and cellular host defences, leading to a syndrome characterized by fever, shaking, chills, hypotension, multiple organ failure, and even death if allowed to enter the circulation in a sufficient dose [see also pyrogen (2.20)].
2.12
endotoxin units
EU
units assayed by the Limulus amoebocyte lysate (LAL) test when testing for endotoxins
Note 1 to entry: Because activity of endotoxins depends on the bacteria from which they are derived, their activity is referred to as a standard endotoxin.
Note 2 to entry: In some countries, endotoxin concentrations are expressed in international units (IU). Since the harmonization of endotoxin assays, EU and IU are equivalent.
2.13
feed water
water supplied to a water treatment system or an individual component of a water treatment system
2.14
haemodiafiltration
form of renal replacement therapy in which waste solutes are removed from blood by a combination of diffusion and convection through a high-flux membrane
Note 1 to entry: Diffusive solute removal is achieved using a dialysis fluid stream as in haemodialysis. Convective solute removal is achieved by adding ultrafiltration in excess of that needed to obtain the desired weight loss; fluid balance is maintained by infusing a replacement solution into the blood either before the dialyser (predilution haemodiafiltration), after the dialyser (postdilution haemodiafiltration), or a combination of the two (mixed dilution haemodiafiltration).
2.15
haemodialysis
form of renal replacement therapy in which waste solutes are removed primarily by diffusion from blood flowing on one side of a membrane into dialysis fluid flowing on the other side
Note 1 to entry: Fluid removal that is sufficient to obtain the desired weight loss is achieved by establishing a hydrostatic pressure gradient across the membrane. This fluid removal provides some additional waste solute removal, particularly for solutes with higher molecular weight.
2.16
haemofiltration
form of renal replacement therapy in which waste solutes are removed from blood by convection
Note 1 to entry: Convective transport is achieved by ultrafiltration through a high-flux membrane. Fluid balance is maintained by infusing a replacement solution into the blood either before the haemofilter (predilution haemofiltration), after the haemofilter (postdilution haemofiltration), or a combination of the two (mixed dilution haemofiltration).
Note 2 to entry: There is no dialysis fluid stream in haemofiltration.
2.17
Limulus amoebocyte lysate test
LAL test
assay used to detect endotoxin
Note 1 to entry: The detection method uses the chemical response of an extract from blood cells of a horseshoe crab (Limulus polyphemus) to endotoxins.
Note 2 to entry: Amebocyte lysate from a second horseshoe crab, Tachypleus tridentatus, can also be used to detect endotoxin.
2.18
manufacturer
entity that designs, manufactures, fabricates, assembles, or processes a finished device
Note 1 to entry: Manufacturers include, but are not limited to, those who perform the functions of contract sterilization, installation, relabelling, remanufacturing, repacking, or specification development, and initial distributions of foreign entities performing these functions. The term does not cover preparation of concentrates from prepackaged dry chemicals at a dialysis facility or the handling of bulk concentrates at a dialysis facility after responsibility for the concentrate is transferred from the manufacturer to the user.
2.19
microbiological contamination
contamination with any form of microorganism (e.g. bacteria, yeast, fungi, and algae) or with the by-products of living or dead organisms such as endotoxins, exotoxins, and cyanobacterial toxins (derived from blue-green algae)
2.20
pyrogen
fever-producing substance
Note 1 to entry: Pyrogens are most often lipopolysaccharides of gram-negative bacterial origin [see also endotoxin (2.11)].
2.21
source water


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