PATHOLOGY AND DIAGNOSTICS
Traceability in laboratory
medicine: what is it and
why is it important?
Reducing the between-method variability in laboratory medicine is required to improve patient outcomes and traceability to
global reference materials and reference methods enables manufacturers to deliver methods that give equivalent results
Graham Beastall
PhD FRCPath
University of Glasgow,
Glasgow, UK
Globalisation affects all areas of life, including
healthcare. For globalisation to have a positive
influence, it is necessary to have global standards
and units to which all measurements are
traceable. We are familiar with global standards
for time, temperature, mass and length and these
standards, coupled with Système Internationale
(SI) units, ensure that these parameters can be
measured anywhere in the world with a small
measurement uncertainty, enabling the safe
transfer of data between global stakeholders.
The same principle should apply to
measurements made, and results used, in
healthcare.
Laboratory medicine is an essential clinical
specialty providing users with pivotal information
for the prevention, diagnosis, treatment and
management of health and disease. Laboratory
medicine has several specialisms including
clinical chemistry, genetics, haematology,
immunology, microbiology and transplantation.
Laboratory medicine results provide information
that impacts a high percentage of clinical
decisions in healthcare. This central role means
that laboratory medicine specialists have a
professional responsibility to provide a high-
quality service that is optimised to the needs of
the patient. 1
A high percentage of laboratory medicine
results are obtained using commercially produced
in vitro diagnostic (IVD) test systems. The global
market for these IVD products was estimated at
$61 billion in 2016, with a growth rate of 4.6% per
annum. 2 Many companies are involved in
producing IVD test systems. Unfortunately, it is
common for the results obtained from different
IVD test systems for the same analyte to be
unacceptably high. Therefore, one increasingly
important quality objective is to ensure that
patient test results are traceable (equivalent)
between different methods, laboratories and
healthcare systems over time. 3
Equivalence of test results is being achieved
through the process of harmonisation in
laboratory medicine. The aim of harmonisation is
to provide accurate, actionable and transferable
patient results, which can facilitate improved
clinical outcomes and patient safety.
Harmonisation in laboratory medicine has a wide
scope. It can be applied across the total testing
process of laboratory medicine, including
requests, samples, measurements and reports. 4
The many dimensions of harmonisation require
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active involvement at local, national and
international levels. 5
The importance of reducing between-
method variability
There are several reasons why efforts should be
made to reduce between-method variability in
laboratory medicine. 4 These include:
• Patient safety: Differences in practice and
variability of results put patients at risk.
Harmonisation of patient results should
contribute to improved clinical outcomes
• Patient empowerment: Healthcare is
increasingly patient-centred. Patients expect
results from laboratories and from self-testing to
be identical and method independent
• Public confidence: The public will be reassured
by the knowledge that patient results are accurate
and transferable between laboratories
• Laboratory accreditation: The ISO 15189:2012
standard used for medical laboratory
accreditation requires trueness of measurement
and metrological traceability
• Clinical guidelines: The successful
implementation of clinical practice guidelines
often links patient management to specific values
or changes in patient results
• Clinical governance: Differences between
patient results leads to concerns about the quality
and professionalism of the service that is
provided
• Consolidation and networking: Laboratory
networks providing services to both primary and
secondary care should be able to provide similar
results from any laboratory site
• Informatics: Laboratory information systems
and hospital information systems will only be
able to share and transfer results if they are
harmonised
• Electronic patient record: National electronic
patient records require that patient results may
be inserted from any laboratory and so they
should be transferable.
Reasons why methods might give different
results on a patient sample
Patients and the public naturally assume that all
methods for measurement of a single analyte will
give the same result on a patient sample. For
some simple analytes, such as plasma glucose, the
results will be very similar. However, for more
complex analytes, the results might vary
considerably. There are many potential reasons