doi:10.1016/j.cca.2005.09.003
Copyright © 2005 Elsevier B.V. All rights reserved.
Nurse-based evaluation of point-of-care assays for glycated haemoglobin
Andrew St Johna,
,
, Timothy M.E. Davisb, Ian Goodallc, Mary Anne Townsendd and Christopher P. Pricee
aARC Consulting, Perth, W Australia 6050, Australia
bUniversity of Western Australia, School of Medicine and Pharmacology, Fremantle Hospital, Fremantle, WA 6160, Australia
cDivision of Laboratory Medicine, Austin Health, Heidelberg, Victoria 3084, Australia
dDepartment of Biochemistry, Fremantle Hospital, Fremantle W Australia 6150, Australia
eDiagnostics Division, Bayer HealthCare, Strawberry Hill, Newbury, Berks, UK
Received 20 July 2005;
revised 2 September 2005;
accepted 2 September 2005.
Available online 3 October 2005.
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Abstract
Background
Various devices are now available to measure glycated haemoglobin (HbA1c) outside of the laboratory. The aim of this study was to assess the performance of these point-of-care instruments in the hands of non-laboratory trained personnel.
Methods
Two nursing staff tested samples from patients attending a diabetes research clinic using the following point-of-care devices for HbA1c-Metrica A1C Now, Bayer DCA 2000, Cholestech GDX and Axis-Shield Nycocard HbA1c. In addition they performed regular analysis of quality control samples. The effects on analytical performance of multiple operators as well as laboratory-trained staff, were also assessed. All measurements were compared to a boronate-affinity HPLC method in the central laboratory.
Results
The mean HbA1c difference of the point-of-care devices compared to the laboratory reference method ranged from − 0.31% to + 0.39%. Only the DCA device had a between batch imprecision of less than 5%. The analytical performance obtained by laboratory staff was similar to nursing staff for 3 devices and better for the Nycocard device.
Conclusions
On the basis of the results obtained by nursing staff, only the DCA of the devices tested, can be recommended for measurement of HbA1c outside of the laboratory.
Keywords: Glycated haemoglobin; HbA1c; Point of care testing; Analytical evaluation
Fig. 1. A. Comparison of A1C Now-HPLC method to mean of A1C Now and HPLC method. Mean HbA1c difference is 0.01% HbA1c (95% CI — 1.01–1.03) N = 112. B. Comparison of DCA-HPLC method to mean of DCA and HPLC method. Mean HbA1c difference is 0.16% HbA1c (95% CI — 0.63–0.96) N = 112. C. Comparison of GDX-HPLC method to mean of GDX and HPLC method. Mean HbA1c difference is − 0.31% HbA1c (95% CI — 1.73–1.11) N = 91. D. Comparison of NycoCard-HPLC method to mean of NycoCard and HPLC method. Mean HbA1c difference is 0.39% HbA1c (95% CI — 0.98–1.76) N = 112.
Fig. 2. Comparison of HPLC, A1C Now and DCA methods as determined by analysis of External QA material.
Table 1.
Assessment of imprecision by duplicate analysis of patient and External QA samples

The External QA material is lyophilized and not suitable for the NycoCard method.
Table 2a.
Within batch precision obtained by nursing and laboratory staff using a blood sample from a normal subject (QC 1) and an abnormal QC material (QC 2) as supplied by the manufacturer of device or from another recommended supplier (n = 10 for all samples)
a Nursing staff used different batches of QC 2 for A1C Now method to those used by laboratory staff.
Table 2b.
Between batch precision obtained by nursing and laboratory staff

QC samples were those supplied by manufacturer of device or from another recommended supplier.
a Nursing staff used different batches of QC 2 for A1C Now method to those used by laboratory staff.
Table 3.
Between operator precision obtained by nursing and laboratory staff each performing two measurements of a normal blood sample

Table 4.
Between reagent batch imprecision assessed by analysis in quintuplicate of two patients samples by each of 3 reagent batches

ANOVA showed that there was significant variance between the means for both samples as measured by the DCA and A1C Now (p < 0.05) but not in the case of the NycoCard.
Table 5.
Effects of method manipulations

Changes to the methods were tested by measurement in triplicate of a normal (5.0% HbA1C) and an abnormal (11% HbA1%) sample. Result obtained from manipulation compared to results obtained with normal procedure.