The SA Journal Diabetes & Vascular Disease Vol 13 No 1 (July 2016)

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VOLUME 13 NUMBER 1 • JULY 2016 19
SA JOURNAL OF DIABETES & VASCULAR DISEASE RESEARCH ARTICLE
before- and after-treatment glucose control, especially in the lower
values, even in the absence of calibration with an HPLC machine.
Consistent with our results, a recent study of HbA1c variations
in Chinese populations living at different altitudes did not find
meaningful variations in the HbA1c levels and the estimated average
glucose levels of patients living in different sites.9
However, on the one hand, Ju et al.9 in their study used the
immunoturbidimetric method for the measurement of HbA1c
levels (also without validation against the gold standard for HbA1c
measurement), while we used a baronate affinity chromatography
to separate glycated from non-glycated haemoglobin for
photometry.4,9 On the other hand, we sought to evaluate the
possible effect of altitude on the accuracy of a POC HbA1c analyser
in patients with diabetes, while they aimed to evaluate whether
altitude could modify the glycation of HbA1c.
In our study, we observed that 12–25% of duplicates had
more than a 0.5% (8 mmol/mol) difference across the sites. The
performance of POC apparatus in general and the In2it in particular
has (independent of altitude) been assessed before. These
investigations constituted a body of evidence showing the need for
improvement in the performance of devices for optimal care.10-12
The recent performance of these devices has given promising
results. This also was the case where the In2it apparatus is concerned,
despite the between-batch variability of results, which still needs to
be addressed.7,13 To circumvent this in our study, we used reagents
from the same lot number at all study sites. However, in daily clinical
practice, this could indeed be a concern for patients’ follow up.
With the generalisation of HbA1c use, especially in developing
countries that have limited access to an HPLC and have a wide
variety of physical environments, it is important to know which
parameters should be taken into account when validating POC
HbA1c devices, which are commonly presented as the adequate
alternative to estimate glycaemic control of patients.
Conclusion
Our results reinforce the need for calibration of POC instruments
against the HPLC in each setting used, to ensure validity of the
readings. We did not find any significant differences when
measuring HbA1c levels at different altitudes on the same samples.
However this requires validation with further studies, using larger
sample sizes and addressing situations with higher proportions of
patients with haematological disorders.
Acknowledgements
This project was supported by BRIDGES, which is an International
Diabetes Federation programme supported by an educational grant
from Lilly Diabetes.
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