Skip to main content
  • Where to buy
  • Company
    • About us
    • Careers
    • Events
  • Support
    • Laboratory Planning
    • Register a Product
    • Register Your Product (USA & Canada Only)
  • Contact
  • U.S.A.
  • Deutschland
  • España
  • France
  • Italia
  • Brasil
  • 日本
  • 中国
Home ELGA LabWater
  • Products
    • PURELAB
    • CENTRA
    • MEDICA
    • BIOPURE
    • ELGA Full Product Range
  • Applications
    • Atomic Absorption Spectroscopy
    • Cell and Tissue Culture
    • Clinical Biochemistry
    • Electrochemistry
    • Gas Chromatography
    • General lab water requirement
    • Immunochemistry
    • Liquid Chromatography
    • Mass Spectrometry
    • Microbiology
    • Molecular Biology
    • Spectrophotometry
  • Technologies
    • Activated Carbon
    • Electrodeionization (EDI)
    • Filtration
    • Ion Exchange
    • PureSure
    • Reverse Osmosis
    • Ultraviolet
  • Impurities In Water
    • Dissolved Gases
    • Inorganic Compounds
    • Microorganisms & Bacteria
    • Organic Compounds
    • Particulates
  • Knowledge
    • Blog
    • Case Studies
    • Ultrapure water
    • Guides and White Papers
  • Products
    • PURELAB
    • CENTRA
    • MEDICA
      • Hubgrade
      • MEDICA BIOX
    • BIOPURE
    • ELGA Full Product Range
      • PURELAB® Classic
  • Applications
    • Atomic Absorption Spectroscopy
    • Cell and Tissue Culture
    • Clinical Biochemistry
    • Electrochemistry
    • Gas Chromatography
    • General lab water requirement
    • Immunochemistry
    • Liquid Chromatography
      • Hochleistungsflüssigkeitschromatographie (HPLC)
    • Mass Spectrometry
    • Microbiology
    • Molecular Biology
    • Spectrophotometry
  • Technologies
    • Activated Carbon
    • Electrodeionization (EDI)
    • Filtration
    • Ion Exchange
    • PureSure
    • Reverse Osmosis
    • Ultraviolet
  • Impurities In Water
    • Dissolved Gases
    • Inorganic Compounds
    • Microorganisms & Bacteria
    • Organic Compounds
    • Particulates
  • Knowledge
    • Blog
      • Analytical Chemistry
      • Clinical & Pharma
      • Cool Science
      • Environment and sustainability
      • Life in the lab
      • Purelab product design
      • Science of the future
      • Water Purity
      • Water in the lab
    • Case Studies
      • Abbott Diagnostics chooses ELGA MEDICA systems in South Asia
      • Beam Me Up, Scotty: PURELAB® Option Q Delivers Essential Ultra Pure Water
      • Argenta chooses DKSH New Zealand to deliver Ultrapure water in Animal Pharma
      • Clean Water for a Clean Future
      • LS Scientific & ELGA deliver UltraPure water to the NAFDAC Laboratory
      • Lifebrain Group chooses ELGA as water partner for new modern 24/7 PCR-COVID-19 laboratory in Vienna, Austria.
      • Critital Tests Benefit from PURELAB® Option Reliable Pure Water
      • DASA: The biggest medical diagnostics company in Brazil
      • ELGA helps immuneserology labs maximize uptime
      • Fondazione Telethon Continues to Choose ELGA Labwater as a Trusted Partner
      • Importance of ultrapure Type 1+ water for the development of generic medicines
      • MEDICA® Pro selected for Siemens ADVIA® analyzers at City General Hospital
      • Optimale Wasserqualität für mikrobiologische Forschung und Lehre
      • PURELAB® Option R Guarantees Pure Water for Leading Microfluidics Technology
      • PURELAB® Pulse Delivers Reliable Water Quality and Quantity for a Wide Range of Applications
      • PURELAB® flex: an ideal training system for today's research method
      • Powering Cutting-Edge Gene Research
      • Sichere Reinstwasserversorgung für präzise Produkttests
      • Zentrale Reinstwasser-Aufbereitung für Analyser
      • ELGA LabWater and Beckman Coulter Join Forces
      • Applied New Technologies Department Improves ICP, IC & HPLC Sample Turnaround Times with PURELAB®
      • Unlocking the secrets of the Antarctic with the aid of ultrapure water
      • Advancing Genetic Technologies
      • Cross Infection Control: Pure and Simple
      • Researching effective new ways to prevent cardiovascular disease at the University of Columbia
    • Ultrapure water
    • Guides and White Papers
      • HPLC Water Purity
      • HPLC in Pharma
      • Reducing Clinical Risks
      • Sustainability
  • U.S.A.
  • Deutschland
  • España
  • France
  • Italia
  • Brasil
  • 日本
  • 中国
  • Privacy policy
  • Terms & Conditions
  • Global Legal Compliance
  • Patents
  • Impressum

Let's talk about lab water

  • Categories
    • Analytical Chemistry
    • Biotechnology
    • Clinical & Pharma
    • Cool Science
    • Environment & Sustainability
    • Future Science
    • Life in The Lab
    • Life Science Results
    • PURELAB Product Design
    • Science of the Future
    • Water In The Lab
    • Water Purity
  • Authors
    • ELGA Editorial Team_cloned
    • ELGA Editorial Team
    • Natasha Zarach
    • Dr Paul Whitehead
    • Dr Alison Halliday
    • John Walker
Water In The Lab
Water Purity

What is CLSI Water?

5 Mar 2020
- by Dr Paul Whitehead

Technology Innovation and medicine clinical laboratory concept

CLSI Water is Clinical Laboratory Reagent Water (CLRW) as defined in Clinical and Laboratory Standards Institute document “Preparation and Testing of Reagent Water in the Clinical Laboratory; Approved Guideline-Fourth Edition”. This is still a key reference document for water purity in clinical laboratories. Collegiate of American Pathologists (CAP) accreditation is used in laboratories around the world. The CAP recommendation is that, as a minimum, water in the laboratory should meet Clinical Laboratory Reagent Water (CLRW) as specified by CLSI.

Clinical Laboratory Reagent Water (CLRW) specification is:

Bacteria     <10 CFU/ml
Resistivity  >10 MΩ.cm
TOC             <500 PPB
Particles     0.2um filtration or better


The CLSI guideline also states that for instrument feed water – “Use of CLRW for this application must be confirmed with the manufacturer of a specific instrument. Water meeting the manufacturer’s specifications must be used.” CLSI clearly anticipate that CLRW may not be pure enough for all analyzer feeds. The onus is on the analyzer company to validate their chemistries and use purified water of a suitable purity to give accurate and reproducible results. 

CLRW Specification Limits 4 Types of Impurity in Laboratory Water

The CLRW specification limits four key types of impurity in pure water:

  • Ions
  • Particulates
  • Organics
  • Bacteria and bacterial by-products


All will impact on clinical analyzer performance, either by direct interference with the chemistries of tests or indirectly, by introducing errors in the measurements.

Ionic Impurities and CLSI Water

The CLRW resistivity specification of >10MΩ.cm restricts the concentrations of ionic impurities to ppb levels or less and, in effect, requires the elimination of carbon dioxide. This is adequate for most clinical work including general chemical, electrolyte, lipid and protein assays, enzymology, enzyme immunoassay, toxicology and therapeutic drug monitoring and, more recent, molecular biological techniques. When trace elements need to be determined, the water resistivity needs to be much higher – at 18.2 MΩ.cm.

Low Levels of Particulates in CLSI Water

The absence of particulates is a general requirement for all types of application and is especially critical with the low liquid volumes used in modern assays. Particles can clog needles and sample handling manifolds. Deposits of particles encourage the formation of bio-film and bacterial growth and can affect the transmissivity and path length of spectroscopic cells. CLRW relies on filtration to remove particulates. However, the 0.2 µm filters specified may not always be adequate.

Total Organic Carbon (TOC)

Similarly, the TOC spec of <500 ppb in CLRW is a reflection of earlier standards and allows scope for the presence of a wide variety of organic compounds such as carboxylic acids and polyaromatics, which could jeopardize assays. Carboxylic acids can interfere with enzymology and enzyme immunoassays by binding to active sites and complexing with co-factor metals. Other organics can inhibit enzymes and affect fluorescent detection.  

Reducing Bacterial Contamination in CLRW

Bacterial contamination has serious effects on all aspects of analyzer operation. The key is achieving consistently low levels. For example, problems can arise in immunoassay due to flurescein-based dye released from bacteria (e.g. Pseudomonas Aureuginosa) giving high blanks and out-of-range standards during calibration and false positives with samples.  
             
Specifications or recommendations are also provided for five other types of purified water to meet different needs in clinical laboratory testing but CLRW is the only one specified in detail. Throughout the document, CLSI emphasizes the need for good practice and rigorous trending of water system parameters for all types of water to ensure that water purity is achieved and maintained. Ultrapure Water must be validated as fit for purpose and water purification system validation is strongly recommended.

Dr Paul Whitehead 

After a BA in Chemistry at Oxford University, Paul focused his career on industrial applications of chemistry. He was awarded a PhD at Imperial College, London for developing a microwave-induced-plasma detector for gas chromatography. He spent the first half of his career managing the analytical support team at the Johnson Matthey Research/Technology Centre,specialising in the determination of precious metals and characterising applications such as car-exhaust catalysts and fuel cells. Subsequently, as Laboratory Manager in R&D for ELGA LabWater, he has been involved in introducing and developing the latest water purification technologies. He now acts as a consultant for ELGA.

 

To discuss your clinical laboratory water requirements, please contact ELGA or an Approved Partner in your country.

Guaranteeing Ultrapure Water In The Lab

Guarantee Your Ultrapure Water Supply Today!

Ultrapure and Pure Water are essential reagents when it comes to working at the limits of analytical detection.

              Download Now

Highlights

16 Jan 2023
Measuring the effects of indoor air pollution
10 Jan 2023
A novel approach to wound healing
12 Dec 2022
3D bioprinting probiotics capsules
4 Nov 2022
Wie mikrobielle Brennstoffzellen zur Lösung von zwei dringenden globalen Umweltproblemen beitragen könnten
24 Oct 2022
New ‘designer drug’ identified in e-cigarettes
6 Oct 2022
Curcumin-beladene Nanopartikel ermöglichen neue Behandlung von Lungenkrebs
3 Oct 2022
Controlling pathogens using natural grapevines extracts
22 Sep 2022
Measuring indigestible sugars in breast milk

Categories

  • Analytical Chemistry
  • Biotechnology
  • Clinical & Pharma
  • Cool Science
  • Environment & Sustainability
  • Future Science
  • Life in The Lab
  • Life Science Results
  • PURELAB Product Design
  • Science of the Future
  • Water In The Lab
  • Water Purity

Video

  • Enquiry
  • Get a Quote
  • Book a Demo
  • Find an Approved Partner

Enquiry

Please check this to confirm that you have read our Terms of Service and Privacy Policy.

Get a Quote

Please check this to confirm that you have read our Terms of Service and Privacy Policy.

Book a Demo

Please check this to confirm that you have read our Terms of Service and Privacy Policy.

Call us

Can't find what you are looking for?

Support Number
+44 (0)20 3567 7300
United Kingdom Sales
+44 (0)1628 879 704
United States of America Sales
+1 877-315-3542
France Sales
+33 1 40 83 65 00
China Sales
+86 400-616-8882

 

ELGA LabWater US Headquarters

ELGA LabWater North America
5 Earl Ct Suite 100
Woodridge, IL 60517
USA

Tel: 630-343-5251

ELGA LabWater UK Headquarters

Lane End Business Park
Lane End, High Wycombe
HP14 3BY
United Kingdom
T: +44 (0) 203 567 7300
F: +44 (0) 203 567 7205

Case Studies

  • Abbott Diagnostics
  • DASA Medical Diagnostics
  • NeoDIN Medical Institute
  • North Staffordshire NHS Trust
  • Olsberg Vocational College

Resources

  • Learn About Ultrapure Water
  • Guides and White Papers
  • Purification Technologies
  • Applications
  • Impurities In Water

Blogs

  • Latest Blog
  • Water Purity - Different Types of Pure Water
  • What is Clinical Laboratory Reagent Water (CLSI)?
  • What is Total Organic Carbon (TOC)?
  • Language
    • Deutsch
    • English
    • Español
    • Français
    • Italiano
    • Português
    • 日本語
    • 中文
  • Other Veolia Sites
    • Veolia
    • Veolia Foundation
    • Veolia Water Technologies

© VWS (UK) Ltd. trading as ELGA LabWater. 2023 - All rights reserved.
ELGA is the global laboratory water brand name of Veolia.

  • Privacy policy
  • Terms & Conditions
  • Global Legal Compliance
  • Patents
  • Impressum
Elga Veolia
TOP

© 2017 ELGA Veolia