What are the quality standards for dialysis water?

Water used for hemodialysis must meet established quality standards to ensure patient safety. Compliance with these standards requires two effective components: a water treatment system that purifies the water according to quality standards, and a distribution system that delivers the treated water to the point of use without re-contaminating it.

Water Treatment System Design

The design and operation of a water treatment system must be based on standards issued by the International Organization for Standardization (ISO). These standards focus on water quality requirements and procedures for installation, disinfection, and maintenance of water treatment systems. ISO standards are reflected in national standards issued by the American National Standards Institute (ANSI) in the United States in collaboration with the Association for the Advancement of Medical Instrumentation (AAMI). Additional mandatory local regulations may also apply.

Water treatment systems must be capable of operating with the available water supply under the worst possible conditions and with a wide range of variations in available water quality. Heavily treated water is highly contaminated, leaching minerals and chemicals from the materials it comes into contact with. Therefore, the surfaces of all components of the water storage and distribution system that will come into contact with the treated water must be made of inert materials; Copper, aluminum, or galvanized metal parts are not permitted.

In-center hemodialysis – The hemodialysis water treatment room must be located within the center in a designated, secure, and access-controlled area. It must be equipped with a water source, drains, and electrical power capable of supporting the operation of the water treatment system. Any newly constructed hemodialysis facility must have a potable water supply, routed separately to the dialysis unit and independent of other on-site water sources. If an existing water source is used, there are potential risks from chemicals used to either limit bacterial growth or to periodically clean the system.

Stages of the Hemodialysis Water Treatment Process

The maintenance department is responsible for ensuring that sufficient potable water is available to the healthcare facility and its facilities 24 hours a day, 7 days a week. The stages of hemodialysis water treatment vary depending on the operating company, but generally, the treatment process is carried out in three stages:

The first stage

This stage is called pre-treatment and consists of several filters, most commonly the following:

• Sand filter to remove impurities.
• Carbon filter to remove chlorine.
• Water softener filter to remove magnesium and calcium.

The second stage

This is called the treatment stage or reverse osmosis stage: The reverse osmosis system uses a pump to push water through a semi-permeable membrane or filter, removing almost all contaminants, including bacteria and viruses.

Read more about Reverse Osmosis systems, one of the technologies CareWater provides to its customers with the highest quality.

The third stage

This is called the post-treatment stage or the disinfection stage, which is performed using thermal heating technology.

Steps for collecting samples of dialysis water produced for bacterial testing

• The sample must be taken by a person trained in the correct method for taking dialysis water samples. This person may be a nurse, a biomedical engineering technician, a dialysis technician, or a specialist from the public health department.
• There must be an approved, written, and documented plan for taking samples for the required periodic tests, specifying the points and methods for collecting samples.
• Preliminary coordination must be made with relevant authorities before taking samples, such as toxicology laboratories, the public health laboratory, the maintenance department, or the biomedical engineering department, to ensure that supplies are available and that samples are received and tested.
• Sample collection supplies must be available, including the following: sterile gloves, alcohol swabs, an ice pack, ice packs, and a sterile 100 ml container. It is preferable to use single-use bottles.

All safety and sterilization precautions must be taken when taking samples.

• Before taking samples, wash your hands thoroughly according to handwashing protocols or use an alcohol-based hand rub, then wear a mask and gloves to ensure the sample is not contaminated.
• Clean the end of the nozzle at the sampling port three times with wipes saturated with 70% isopropyl alcohol and 2% chlorhexidine, then wait for the nozzle to dry.
• Open the water valve and run it for 2 to 3 minutes to circulate the water before taking the sample.
• Open the lid of the sterile container to collect the water sample without touching the sampling point. Do not rinse the container or place the lid on the surface, but hold it on the outside of the container with your hand.

Fill the vial below the 100 ml line, leaving about an inch of space.

• Immediately, tightly cap the vial and place it in the container.
• The name of the healthcare facility, sample number, location, date and time of sample collection, and the name of the person collecting the sample must be printed on the vial, or the barcode must be printed from the Otar system and placed on the sample. When recording sample information, a material that cannot be removed or blurred by moisture, humidity, or the like must be used.
• Water samples must be kept cool (4°C-1°C) and not frozen. They must be sent immediately to a specialized laboratory, preferably within a maximum of twenty-four (24) hours.
• Pre-arrangement with the laboratory before taking samples is necessary to ensure the samples are received and tested.
• Follow up on receiving sample results from the laboratory.
• Record and store analysis results in special records maintained by the facility’s Public Health. Or Environmental Health Department, and provide other departments with the results as appropriate.
• The maintenance department must notify the Public Health or Environmental Health Department of any planned or unplanned interruption in the water supply to the dialysis water treatment plant, or of any damage to the dialysis water network that could lead to water contamination.

Source: Guideline for Monitoring the Quality of Dialysis Water – Saudi Ministry of Health

Normal Chemical Specifications for Hemodialysis Water

The most widely used and required standards are those recommended by the Association for the Advancement of American Medical Instrumentation (AAMI). The following table shows the normal levels of chemical contaminants permitted in hemodialysis water:

Treated water is not permitted for use in the dialysis process if the level of any chemical contaminants exceeds the permissible level. Treated water may not be reused until the necessary corrective measures (depending on the type of contaminant) are implemented by the treatment plant operator or the Biomedical Engineering Department. The retesting is then completed, and results are received showing that the chemical contaminant level has returned to normal.

Read more about the importance of Reverse Osmosis plants for dialysis units.