Cardiovascular Journal of Africa: Vol 26 No 1 (January/February 2015)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 1, January/February 2015 40 AFRICA
no significant difference was observed between HbA1c levels
at the three altitudes, the POC apparatus had a relatively high
variability between 13 and 1 600 m.8 As expected, this variability
was higher in low and normal HbA1c levels (not shown).
In this regard, the use of the POC HbA1c analyser could
be more indicated for the monitoring of patients with a
view to comparing 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 HbA 1c 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.
This project was supported by BRIDGES. BRIDGES is an International
Diabetes Federation programme supported by an educational grant from
Lilly Diabetes.
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