Copyright © Royal College of pathologists of Australasia. Unauthorized reproduction of this article is prohibited.
Evaluation of point-of-care testing in critically unwell patients:
comparison with clinical laboratory analysers and applicability to
patients with Ebolavirus infection
JEN KOK
1,2,3
,JIMMY NG
1
,STEPHEN C. LI
4
,JOHN GIANNOUTSOS
5
,VINEET NAYYAR
6
,
JONATHAN R. IREDELL
1,2,3
,DOMINIC E. DWYER
1,2,3
AND SHARON C-A. CHEN
1,2
1
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical
Research, Pathology West, Westmead Hospital, Westmead,
2
Marie Bashir Institute for Infectious Diseases and
Biosecurity, University of Sydney, Westmead Hospital, Westmead,
3
Centre for Research Excellence in Critical
Infections, University of Sydney, Westmead Hospital, Westmead,
4
Department of Core Pathology and Clinical
Chemistry, Institute of Clinical Pathology and Medical Research, Pathology West, Westmead Hospital, Westmead,
5
Department of Hematology, Institute of Clinical Pathology and Medical Research, Pathology West, Westmead
Hospital, Westmead, and
6
Department of Intensive Care Medicine, Westmead Hospital, Westmead, NSW, Australia
Summary
Data on the performance of point-of-care (POC) or near-
patient devices in the management of critically unwell patients
are limited, meaning that there are demands for confirming
POC test results in the routine clinical laboratory and so
potentially leading to delay in treatment provision. We eval-
uated the performance of the i-STAT CHEM 8þ and CG4þ,
Hemochron Signature Elite, HemoCue Hb 201þ and WBC
Diff Systems on whole blood collected from medical and
surgical patients admitted to the intensive care unit at an
Australian tertiary care hospital. Measurements obtained for
haematology, coagulation, biochemistry and arterial blood
gas parameters using POC devices were compared against
clinical laboratory analysers (XE-5000, STA-R Evolution,
Dimension Vista 1500 and ABL800 FLEX). Bland–Altman
and Passing–Bablok regression plots were constructed to
assess agreement. Good correlation was defined as a bias of
<10% between the POC device and the reference method.
Forty arterial blood samples were collected from 28 patients.
There was good correlation demonstrated for sodium, pot-
assium, chloride, ionised calcium, glucose, urea, haemo-
globin and haematocrit values (i-STAT Chem 8þ); pH,
pCO
2
, bicarbonate and oxygen saturation (i-STAT CG4þ);
haemoglobin, white cell, neutrophil count and lymphocyte
counts (Hemocue); and internationalised normal ratio (INR;
Hemochron Signature Elite), but not creatinine, anion gap,
pO
2
, base excess, lactate, eosinophil count, prothrombin and
activated partial thromboplastin time. POC devices were
comparable to clinical laboratory analysers in measuring
the majority of haematology, biochemistry and coagulation
parameters in critically unwell patients, including those with
infections. These devices may be deployed at the bedside to
allow ‘real-time’ testing to improve patient care.
Key words: Biochemistry, coagulation, diagnostics, haematology, point-of-care.
Received 27 April, revised 9 June, accepted 9 June 2015
INTRODUCTION
Point-of-care (POC) testing is the fastest growing sector in the
clinical in vitro diagnostic market, and is increasingly being
used to improve patient outcomes by providing faster turn-
around times (TAT). Traditional POC testing methods using
immunochromatography and wire-guided droplet microfluidics
for physiological measurements have been further complemen-
ted by multicore processors, microchips, high-resolution cam-
eras and wireless communication to advance POC testing in
areas of infectious diseases, cancer and cardiac care.
POC devices have the advantage of not requiring specialised
laboratory equipment or expertise to operate, making them
suitable for near patient deployment to provide rapid results in
‘real-time’ which translates to improved clinical decision-mak-
ing and quality of care, and potentially lower healthcare costs.
Confirmation of a clinical diagnosis by POC testing further
obviates unnecessary testing and allows the timely provision of
specific therapies. In the example of Ebolavirus infection or
other diseases in remote settings, POC testing may be an
alternative where routine laboratory services are unavailable,
or when use of laboratory analysers may be inappropriate.
Data are limited on the performance of POC devices in
critically unwell patients, particularly ‘in the field’. Some POC
devices were developed for specific populations in specific
settings, and may not be fit for purpose when used outside these
instances. Herein, we evaluate the performance of several POC
devices in measuring haematology, coagulation, biochemistry
and arterial parameters in critically unwell patients, and com-
pare results obtained to clinical laboratory analysers.
METHODS
Clinical samples
Arterial blood samples were collected from medical and surgical patients
admitted to the intensive care unit (ICU) at Westmead Hospital, a tertiary-level
hospital with trauma, solid organ and high-risk haematopoietic stem cell
transplantation services, and placed into the appropriate blood tubes [BD
Vacutainer K2E (EDTA), LH PST II (lithium heparin) and Citrate tubes
(3.2% sodium citrate; Becton Dickinson, USA)].
Samples were collected in duplicate, and tested immediately after collection
in four separate POC devices: (1) i-STAT (Abbott Point of Care, USA), (2)
Hemochron Signature Elite (ITC, USA), (3) HemoCue Hb 201þ, and (4)
HemoCue WBC Diff System (HemoCue, Sweden). Table 1 details the tests
Pathology (August 2015) 47(5), pp. 405–409
LABORATORY PREPAREDNESS FOR EBOLAVIRUS
Print ISSN 0031-3025/Online ISSN 1465-3931 Copyright # 2015 Royal College of Pathologists of Australasia. All rights reserved.
DOI: 10.1097/PAT.0000000000000296