Water in the Clinical Laboratory
 Role of water in Clinical Diagnostic
 Purification technologies basics
 Delivering water to the clinical analyzer
Mikael Cleverstam
WW Clinical Business Manager
1
Putting it all together
Troubleshooting Your analyzer
Diagnostic instruments
Assay development
Patient results
CLSI New standards
Water quality as part
of the quality process
Water purification
Quality system
Diagnostic
Instruments
Water
Quality
Medical
Technologist
Quality Control
Patient
Results
2
Normal seen Problems
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Frequent Calibrations
High CV%
Fluctuation in quality results over the day/week/month
Interfered assays
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Calcium
ALP
CK
Amylase
LD
Phosphorus
Iron
Magnesium
Triglycerides
Urea
Troponin I
Interfered by rocks, leaves, geology
Interfered by biofilm, detergent, rocks
Interfered by water treatment
Interfered by citrus fruit, detergents, leaves
Interfered by effluent, leaves, H2O2
Interfered by citrus fruit, leaves
Interfered by rocks, leaves, detergents
Interfered by citrus fruit
Interfered by plastics, chemicals
Interfered by citrus fruit, water treatment
Interfered by biofilm
3
Water for Clinical Analysers
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Cuvette washing
Tubing and probe rinsing
Reagent and buffer reconstitution
Dilution
Water Baths
4
Clinical Analyzers
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Features and benefits of automation
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Diagnostic
Instruments
Precision optical systems for accuracy in testing
Automatic sampling and dilutions modes
Real time alerts to patient and QC failures
Improved software alerts end user to mechanical failures
Cost benefits
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Workflow efficiency and high speed through put
Instrumentation targeted to reduce operating cost with more
efficient technology
Reduced operator interface
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Assay Development
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Diagnostic
Instruments
Measuring chemical changes in the body for diagnosis, therapy and
prognosis has resulted in new assay development
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Multiple method testing on a single analyzer
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Current research methodologies for infectious disease and tumor
marker’s are moving from research labs in universities to the clinical
laboratory
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Complex methodologies are being fully automated for more routine use
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Unique Challenges for Medical Technologist
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Medical
Technologist
Verification of final clinical results to be accurate and precise are
determined by Medical Technologist
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Clinical decisions are not solely made on the test result, but in
conjunction with the patient’s history and symptoms
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Software alerts, QC reviews, calibration must all be within stated limits
before results are released
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Troubleshooting instrument problems result in production delays, are
costly and non-productive activities that must be performed and
documented
➙ Try to avoid diagnostic instrument service because it is expensive
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Reviewing Patient Results
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All analytical and pre-analytical factors must be reviewed and
documented
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Medical Technologist must review all test results

If results are flagged, troubleshooting the cause is necessary
Diagnostic
Instruments
Quality Control
Medical
Technologist
Patient
Results
8
Troubleshooting procedures
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Sample handling procedures confirmed
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Quality control must be reviewed
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Assay
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Reagent issue
Calibrator stability
Mechanical
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Shifts and trends
Peer group
Previous data
Diagnostic
Instruments
Quality Control
Medical
Technologist
Patient
Results
Instrument malfunction
Error codes
If above solutions do not correct the erroneous result, further
troubleshooting must identify cause before results can be released to
physicians
➙ Delayed patient treatment.
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Diagnostic
Instruments
Next Steps
Water
Quality
NO
Problem
Assay
Medical
Technologist
YES
NO
Mechanical
YES
Decontamination
YES
Problem
solved
Outside Source
WHY ??
Water Quality
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Water Quality
Water
Quality
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Quality results are dependent upon reliable instrumentation and
known water quality
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Analytical factors need to be controlled and optimized to reduce the
number of test failures, failed calibrations, and high blanks that can
contribute to erroneous patient results
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Maintenance of high purity water system is essential to reliable results
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Understanding Water Quality
and Methodology
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Water should be considered a bulk reagent on any analyzer
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Water
Quality
The high purity water system is a separate unit, not monitored by
diagnostic software on the clinical analyzer
The unique properties of water if not processed and monitored can
produce subtle changes in assay methods
These changes in water quality can lead to erratic and inconsistent
results
The quality of water required or its impact on the testing method
is often not considered until the purchase is complete
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Diagnostic Dilemma
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Smaller sample size and reaction vessel are subjected
Diagnostic
Instruments
Water
Quality
to harsher environment
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Inevitable build-up of biofilm in instruments, manifolds and tubing
require more frequent decontaminations
but
Less and less time available for maintenance of the instruments
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Some sensitive assays can become contaminated with bacteria and
ions
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Bacteria release enzymes and ions whose behavior is similar to the
enzymes targeted in the assay method
➙ Increased need to monitor water quality as closely as any other
instrument malfunction
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Biofilm Formation
Diagnostic
Instruments
Water
Quality
Organic
Particles
Surface
Bacteria
Time
Biofilm may shed bacteria, pyrogens etc
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Demonstration of ALP release from bacteria
Diagnostic
Instruments
Water
Quality
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Correlation between bacteria concentrations and levels of ALP in
water
Bacteria Strain
(identification by 16S rDNA sequencing)
Bacteria level
(x 106 cfu/mL)
ALP concentration
(mUnit/mL)
Sphingomonas paucimobilis
29.2
6.22
Caulobacter crescentus
9.7
9.95
Ralstonia pickettii
29.5
8.29
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Diagnostic
Instruments
Detection methods
Substrate-Phosphate
Water
Quality
ALP
+
Pi
UV-Visible
 pNPP
Fluorescence
 Attophos
 Starbright
 MUP
 ELF
Chemiluminescence
 CDP-Star (dioxetane)
 CSPD (dioxetane)
 Lumigen PPD
 AMPPD
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Quality Control
CLSI Water Quality Standards
Water
Quality
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New Standards released July 2006 (C3-A4 Vol. 26 No. 22)
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Nomenclature Type I,II,III has been replaced with purity types that
provide more meaningful parameters
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CLRW (Clinical Laboratory reagent Water) replaces Type I,II for most applications
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IFW (Instrument Feed Water) allows instrument manufacturers to clarify specifications
for their particular methods
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SRW ( Special Reagent Water) may be specified for specific applications when
additional parameter are needed to insure water quality
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Autoclave and wash water will meet the requirements of previously classified Type III
Complete review of the document should be done when considering
new applications to insure the contaminants found in the source water
do not become an issue
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Water Contaminants
Water: H2O …. and some other things
Presence of contaminants
Particles
Gases
Purification technologies
Microorganisms
H
Ions
H
H
Organics
H
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Protecting the Water Purification Unit:
Pretreatment cartridge
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Due to the difference in water
quality around the world, additional
pretreatment cartridges are
required.
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The cartridges provide protection
and insure good performance of the
reverse osmosis membrane
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The pretreatment packs include 0. 5
micron filter (1) to remove particles
and activated carbon (2) to remove
chlorine
The activated carbon is
impregnated with a small level of
silver to prevent bacterial growth.
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Example of a
pretreatment cartridge
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What is reverse osmosis ?
P
P
Feed Water
Reject
Permeate
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Technology Insight: Electro-Deionization
EDI module
- Ion selective membranes
- Ion exchange resins
- Continuous current
Reverse Osmosis Water
10 - 20 mS/cm
A
H+
+
Anode
Cl-
C
A
Na+
Cl-
Cl- Na+
OHNa+
-
OH-
H+
Cl-
C
Na+
Cl-
Cathode
Na+
Reject
Product
A - Anionic Membrane
C - Cationic Membrane
Resistivity: > 10 MW.cm
TOC: < 30 ppb
No need for regeneration
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Filters – Bacteria Removal
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Screen 0.2 µm filters
Designed for the removal of particles and microorganisms from
liquids and gases.
Use of PVDF membranes, provide high flow rates and
throughputs, low extractables, broad chemical compatibility and
the lowest protein binding of any membrane available.
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Ultrafiltration
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Cut-off: 5 KDa to 20 KDa
Removes bacterial by-products such as most proteins and
macromolecules (e.g. endotoxins)
Utilized for immunochemistry assays
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Immunoenzyme assays based on reporter enzymes (alkaline
phosphatase, ALP) are sensitive to ALP released by bacteria
Also filters bacteria
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Storage
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CLRW water with a resistivity >10 megohm-cm cannot be stored
because ionic and organic contamination will leach from the
atmosphere and container materials in which it is stored.
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CLRW water should be used as it is produced
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Stored water is never as pure as when it is made
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Storage of water enhances bacterial contamination
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Containers need to be cleaned thoroughly between refilling.
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Carboys, tanks, bottles
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Notorious source of contamination since we often refill them without
thoroughly cleaning them when they are emptied
Some plastic materials out-gas polymers and plasticizers, and
these end up in the water
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Water Purification Unit
Simplified flow schematic combining purification technologies
Tank
Pretreatment
cartridge
Feed
water
Reverse Osmosis
cartridge
Electrodeionization
module
Resistivity
cell
Pump
To analyzer
UV
Germicidal
Drain
Ion exchange
resins
The electrodeionization module is not present in some purification units
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Connecting the Water Purification Unit to the
Clinical Analyzer
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Water is delivered in its purified state to a harsh environment
within the chemistry analyzer bottle
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Water bottles inside analyzer are not frequently decontaminated
Electronics, mechanical hardware, pumps all create heat within the
analyzer cabinet, thus raising the interior temperature of the water
bottle.
Increased temperatures enhance the growth of bacteria and biofilm
within the instruments manifolds and tubings.
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Conclusions
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Water is a reagent.
The quality of water has an impact on the testing method.
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