scope:

A number of types of purified water for use in clinical laboratory testing procedures are specified:

• clinical laboratory reagent water (CLRW);
• special reagent water (SRW);
• instrument feed water;
• water supplied by a method manufacturer;
• autoclave and wash water; and
• commercially bottled, purified water.

Procedures are provided for measuring parameters that monitor ionic, organic, and microbial contamination in purified laboratory water. These parameters should be monitored over time to identify trends in performance so corrective action can be taken before a parameter exceeds specified limits. Recommendations are provided to control particulate and colloidal contamination. The guideline includes validation by the laboratory that a selected type of water is fit for its intended purpose. Suggested approaches for validation of water purification systems are included.

It is beyond the scope of this guideline to recommend specific types of water purification systems. Instead, the guideline provides information about discrete purification technologies and monitoring strategies that can be applied in various combinations to achieve and maintain the required water purity.