CLSI Publishes New Guideline for Preparing, Testing of Reagent Water
July 12, 2006
The new Clinical and Laboratory Standards Institute (CLSI) document, Preparation and Testing of Reagent Water in the Clinical Laboratory; Approved Guideline - Fourth Edition (C3-A4), provides information on water purity requirements for clinical laboratory testing, validation of specifications, technology available for water purification and test procedures to monitor and trend water purity parameters.
Purified water constitutes the major component of many reagents, buffers and diluents used in clinical laboratory testing. It can become an indirect component of tests when it is used for washing and sanitizing instruments and laboratory ware or generating autoclave steam. Inadequate control of contamination in purified water is a potential cause of laboratory error.
The document outlines procedures for measuring parameters that serve as indicators for the total ionic, organic and microbial contamination in purified laboratory water and emphasizes the value of trending these parameters as an effective way to control the quality and consistency of purified laboratory water and the importance of validating that a given type of laboratory water is fit for its intended purpose. A new section provides guidelines for water purification system validation, ongoing maintenance and revalidation on a recurring schedule.
The revised guideline includes updated information regarding the preparation and testing of reagent water in clinical laboratories. Type I, II and III designations for types of purified laboratory water have been replaced with more meaningful specifications for clinical laboratory testing. The guideline recognizes that organic contamination, which can be difficult to remove from feed water, must be controlled and emphasizes continued specification of the plate counting of colonies approach. Also, epifluorescence and endotoxin testing have been added as optional tests because they provide additional information and results can be determined quickly.
Source: Clinical and Laboratory Standards Institute (CLSI).