Quality Control for Point of Care Testing - White Paper

QC Explained 1. 0 - Quality Control for Point of Care Testing
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QC Explained 1.0 - Quality Control for
Point of Care Testing
Kee, Sarah., Adams, Lynsey., Whyte, Carla J., McVicker, Louise.
Background
Point of care testing (POCT) refers to
testing that is performed near or at the
site of a patient with the result leading
to a possible change in the care of the
patient. Over the past few years, the
popularity and demand of POCT has been
growing rapidly. This should come as no
surprise as there are many advantages to
POCT, for example, the added
convenience of being able to obtain a
rapid result at the patient’s bedside, thus
allowing immediate action, saving time
and improving the potential outcome for
the patient.
Although there are many benefits of using
POCT devices in terms of their
convenience, these benefits are only true if
the results produced are both accurate
and reliable. Ensuring accuracy and
reliability is the primary responsibility of
Quality Control.
Quality control is composed of two key
elements; internal quality control (IQC)
and external quality assessment (EQA). IQC
involves running quality control material
that contains analytes of known
concentration to monitor the precision of
the analytical process over time. Whereas
EQA involves running blind patient-like
samples, comparing your results to peer
results, in order to retrospectively monitor
the accuracy of reporting. EQA samples
should be treated as if they were a patient
sample and therefore must be run by
personnel who would be using the device.
This provides confidence in the reliability
of patient test results.

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Content
Section Title Page
1.0 Importance of Quality Control for POCT Devices 3
2.0 Who is Responsible for QC in POC Testing? 4
3.0 Choosing an Appropriate QC Procedure for your POCT Device 4
3.1 Balancing risk with the stringency of your POCT quality
control procedure
4
3.1.1 Choosing a QC procedure for High Throughput Analyser
Type POCT Instruments
5
3.1.2 Choosing a QC procedure for Cartridge Based Instruments 5
3.1.3 Choosing a QC procedure for Strip Based Instruments 6
3.1.4 Choosing a QC procedure for manually read POC Tests 7
4.0 Choosing IQC material and an EQA scheme that’s appropriate for
use with POCT devices
7
4.1 Choosing IQC material for POCT devices 7
4.2 Choosing an EQA scheme for POCT Devices 8
5.0 Additional Software Available 8
6.0 Conclusion 9
7.0 References 9

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1.0 Importance of Quality Control for POCT Devices
ISO 15189 states that “Quality Control
materials shall be periodically
examined with a frequency that is
based on the stability of the procedure
and the risk of harm to the patient from
an erroneous result” (1). Therefore, when
implementing a QC strategy for POCT
devices the risk of harm to the patient
should be the foundation of the plan:
where and why do errors occur and what
are the consequences of an erroneous
result to the patient? It is important to
balance the risk of harm to the patient
with the stringency of the QC procedure
applied. Inaccurate results can have
serious implications for the patient
including misdiagnosis and/or
inappropriate or incorrect medical
procedures being carried out
unnecessarily, resulting in monetary
implications for the hospital.
POCT procedures have been previously
shown to be less stable than those run
within the laboratory. For example, a study
undertaken by the Ontario Laboratory
Accreditation body found that POCT is the
largest source of error in the laboratory
when compared to other sources of error
(2) (see figure 1). This demonstrates the
definite need for a well-designed QC
procedure in a point-of-care (POC) setting
to minimise the risk associated with POCT
devices. Furthermore, another recent study
found that the most common phase for
errors in POCT was analytical, with 65.3%
of errors occurring during this phase. (3)
Conversely, in laboratory based testing the
analytical phase is the least common
source for errors (4) thus, highlighting the
importance of QC procedures for POCT
devices while also outlining how the
potential risk of harm to a patient may be
greater for POC tests compared to those
performed on laboratory based analysers.
This study also revealed that the potential
impact of quality control error on a POCT
device having a moderate adverse impact
Figure 1: Ontario
Study

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on patient outcome was 14.7% (3),
demonstrating that for POCT devices there
is larger room for error and a greater need
for quality control.
Some POCT device manufacturers advise
that QC procedures similar to those found
in the laboratory are unnecessary for POCT
devices. However, this is not the opinion
of the majority of laboratory professionals
who believe a place undoubtedly remains
for traditional IQC and EQA practices for
POCT. This view is supported by the
introduction of the new ISO POC specific
regulations. In 2006 a new ISO standard;
ISO 22870 was released specifically for
POCT titled: “POCT – Requirements for
quality and competence” (5). ISO 22870
advises that where available, Internal
Quality Control and participation in an
External Quality Assessment scheme is
required in the point of care setting. ISO
22870 is designed to be used in
conjunction with IS0 15189.
2.0 Who is Responsible for QC in POC Testing?
According to ISO 22870:2006 a POCT
management group should be set up with
responsibility for managing and training
staff using the equipment. This group
should be responsible for the quality
management strategy and implementation
of a staff training programme which
includes quality control, for all personnel
performing POCT and interpreting results
from a POC device.
Additionally, running of QC samples on
POC devices should be performed by
those who are using the devices regularly,
as QC samples should be run as if they
were a patient sample and therefore must
be performed by personnel who are
responsible for and undertake patient
testing.
3.0 Choosing an Appropriate QC Procedure for your
POCT Devices
3.1 Balancing risk with the stringency of
your POCT quality control procedure.
There are many risk factors that should be
considered when designing the stringency
and frequency of any POCT QC strategy.
The greater the risk, the more stringent
the QC procedure should be. When
designing an appropriate QC strategy
there are a number of risk factors that
need to be taken into consideration:
 high risk tests with large impact for
the wrong result,

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 tests used to support the clinician’s
decision in isolation,
 tests acted upon immediately, and
 tests performed on specimens that
are difficult to collect.
The POCT strategy will depend on the POC
device that is being used as POCT devices
can be broadly split into three categories:
1. “High Throughput Analyser”- Full size
instruments used at the point of care,
e.g.: blood gas analysers.
2. “Cartridge Based Instruments”- For
example HbA1c and INR analysers.
3. “Strip Based Instruments” e.g.:
electrochemical or reflectance strip
based glucose meters and INR
analysers.
4. “Manually read Tests” e.g.: urine
dipstick test.
3.1.1 Choosing a QC procedure for a
High Throughput Analyser Type
POCT Instruments.
A high throughput analyser mirrors those
found within the laboratory and therefore,
the quality control procedure should
mirror that seen within the laboratory.
Multi-level true third party controls should
be tested a minimum of once per day,
each day a patient sample is tested; in line
with ISO 15189 regulations. Depending on
the test in question and the number of
patient samples processed, quality control
frequency may need to be increased.
Not all IQC material can be described as
third party, as a third party control is one
which has not been designed or optimised
for use with a specific instrument or
reagent, therefore providing an unbiased,
independent assessment of analytical
performance. The accuracy and reliability
of those results should be monitored over
time to provide a true reflection of
performance.
According to ISO 22870 EQA should be
performed on all POCT devices. EQA is
useful both as an assessment of the
reliability of patient results and to help
identify internal staff training needs.
3.1.2 Choosing a QC procedure for
Cartridge Based Instruments.
For cartridge based instruments the
technology differs from that found in
standard laboratory type analysers.
However the use of third party controls is
still essential to ensure optimised
performance and accuracy.
Cartridge based devices usually consist of
two components: a cartridge based
component, and an electronic reader
based component. The cartridge based
component contains all of the necessary
“ingredients” for the analysis of the patient
sample, while the electronic reader
component is responsible for converting
the result from the cartridge component
into a numerical value for analysis.
There are many possible sources of error
with cartridge based devices: the cartridge
may have been damaged during transport,
the on-board reagents may have
deteriorated over time, the electronic
reader may become defective or the
operators of the devices may not be
adequately trained to use the device
appropriately.

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Each time the laboratory receives a new
batch of cartridges they should be
evaluated using multi-level, third party
controls to ensure that the cartridges have
not been damaged during transport. It is
also a good idea to periodically test
quality control samples over the shelf life
of a particular batch.
Ideally a third party control should be
used every day of patient testing to ensure
the stability of the on-board reagents and
the accuracy of the results obtained, as
recommended by ISO 15189. However, it’s
important to note that when using QC for
cartridge based devices it is only the
performance of that one cartridge being
analysed at that particular time. In
addition some cartridge based devices
have their own inbuilt QC self-check
function. Therefore, running QC daily may
not be entirely necessary however, in
doing so the laboratory is instilling
confidence that reliable patient results are
released.
On the other hand, for instruments
without a built in QC function, multi-level
third party controls should be used daily
to ensure the reliability of results. In
accordance with ISO regulations, EQA
should be performed for all cartridge
based devices.
Strip Based Instruments.
Finally, strip based instruments are very
similar in design to cartridge based
instrument. Like cartridges, the strips are
responsible for the analysis of the sample
however, unlike cartridge based devices
the electronic component has no QC self-
check feature and without this feature a
faulty analyser could produce erroneous
results which may remain undetected for
some time. Due to this, QC processes
should be more stringent for strip based
devices than cartridge based devices to
ensure the accuracy and reliability of the
system. Strips should be checked on
delivery using multi-level third party QC to
ensure they have not been damaged
during transit in addition to every day of
patient testing. EQA should also be
performed for strip based devices.
manually read POC Tests.
It is essential to use both IQC and EQA for
manually read tests, e.g.: the urine dipstick
test. There is a higher degree of human
error with manually read tests as results
can vary depending on different
interpretations and therefore there is a
greater need for quality control. Using IQC
and EQA will help to standardise results
and ensure that reliable results are
released.

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4.0 Choosing IQC material and an EQA scheme that’s
appropriate for use with POCT devices
As discussed above, all POCT devices
should run third party IQC samples and
perform EQA. It is important to choose
IQC material and an EQA scheme that fully
meets the needs of the laboratory.
4.1 Choosing IQC material for POCT
devices
When implementing an IQC strategy it is
important to take into consideration the
differing designs of the device and
potential risk of harm of the patient. When
choosing an appropriate QC material look
for the following features:
 Ease of use – many samples are
available in a ‘liquid-ready-to-use’
format which require no preparation.
This format can be conveniently
stored at +2 to +8o
C meaning it can
be stored safely on the ward rather
than in a laboratory freezer.
 A matrix similar to the patient
sample – choose samples that are as
close to a human sample as possible,
in-line with ISO15189 regulations.
 Clinically relevant concentrations –
analytes should be available at
clinically significant concentrations to
accurately validate patient sample
results.
 Accurately assigned - method/
instrument specific target values and
ranges should be accurately assigned.
 Third party – ISO 15189 recommends
quality control material is from a third
party source.
4.2 Choosing an EQA scheme for POCT
Devices
EQA is strongly recommended for all
point of care devices. ISO 22870:2006
states, “There shall be participation in
external quality assessment schemes”.
There are many EQA schemes available
for POCT devices, it is important that you
choose a scheme that offers:
 Frequent reporting to minimise the
amount of time an error can go
unnoticed.
 Quality material in a format suitable
for use with POCT devices.
 Well-designed reports that allow for
quick and easy troubleshooting of
erroneous results at a glance.
 Multiple instrument registrations for
each EQA sample provided, helping to
save money and monitor performance
across all POC instruments.

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5.0 Additional Software Available
Perhaps a reason for the higher rate of
error associated with a POCT device is due
to a lack of responsibility on behalf of the
staff performing the POCT. Ultimately,
responsibility should lie within the
laboratory but how can the quality of
results released by POCT devices be
managed when the people performing the
tests are spread out in a hospital setting,
and out of direct view of the laboratory
QC Technician?
The review process can be facilitated by
QC management software, which helps the
laboratory monitor the reliability and
accuracy of results released in the POC
setting.
There are a number of QC management
programs available, however the following
requirements should be sought after:
 Up to date peer group – Ideally a QC
management program should have a
peer group functionality to enable the
comparison of results to other
laboratories worldwide using the
same lot of control, method and
instrument. Peer group monitoring
should be in real time, and therefore,
should be updated daily.
 Multiple instrument registrations –
the ability to register multiple
instruments is vital in POCT as there
will be a number of POCT devices
through the POC setting that will
need monitored.
 Online access – within a POC setting
it’s important that results can be
entered online, anywhere at any time.
This also means that the lab manager
can remotely log onto the software to
view the QC results entered for
specific POC devices throughout the
hospital or beyond.
 Multiple user levels - Different user
level accounts should be available so
that lab managers can track results.
This also ensures that each POC
operator is performing appropriate
maintenance, instrument calibration
and is adequately trained to use the
device.
 User defined acceptable limits - to
be applied to QC results, so that
results can automatically be rejected
or accepted.
Indeed major sources of error have been
previously categorised to be commonly
due to operator incompetence and a
disregard for test procedures, and the use
of uncontrolled reagents and testing
equipment (6). Therefore, through using
appropriate QC management software in
the POC setting, the laboratory can reduce
the level of risk and ensure accurate
results are obtained.

QC Explained 1
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6.0 Conclusion
It is important to remember that the
benefits of using POCT devices are only
true if the results obtained are accurate
and reliable however given the large
number of POCT devices available on the
market choosing an appropriate quality
control plan for your instrument can be
challenging. By following the guidelines
outlined in this paper in addition to ISO
15189 and ISO 22870:2006 you can be
assured that the management and overall
results of your POCT devices will be of a
higher and more reliable quality.
7.0 References
1. ISO 15189:201, Medical laboratories -Requirement for quality and competence.
2. Ontario laboratory accreditation programme, non-conformances identified in sites seeking
accreditation.
3. O'Kane, Maurice J., et al. "Quality error rates in point-of-care testing." Clinical chemistry
57.9 (2011): 1267-1271.
4. Kazmierczak, Steven C. "Point-of-care testing quality: some positives but also some
negatives." Clinical chemistry 57.9 (2011): 1219-1220.
5. ISO 22870:2006, Point-of-Care testing (POCT) – Requirements for quality and competence
6. Meier, Frederick A., and Bruce A. Jones. "Point-of-care testing error: sources and amplifiers,
taxonomy, prevention strategies, and detection monitors." Archives of Pathology and
Laboratory Medicine 129.10 (2005): 1262-1267.

Quality Control for Point of Care Testing - White Paper

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Quality Control for Point of Care Testing - White Paper