Reliable Diabetes monitoring parameter
Compiled by : Prateek
Embee Diagnostics Pvt. Ltd
HbA1c is a modified form of haemoglobin.
Haemoglobin is the molecule in our red blood cells which carries
oxygen around the body; most of the haemoglobin is of a type
called HbA. A small fraction of HbA becomes modified during its
lifetime (HbA1). In the late 1950s it was found that HbA1 could
be separated further into HbA1a, HbA1b and HbA1c. A decade
later, the clinical significance of HbA1c became apparent when
it was revealed that many diabetics had uncharacteristically
high levels of this haemoglobin variant.
HbA1c is formed when glucose molecules
attach to HbA molecules in a process known as glycosylation.
Glycosylation reactions are common and occur naturally in the
body. Normally though, they take place in a controlled
environment, regulated by enzymes. The process by which HbA1c is
formed, however, occurs in the absence of enzymes and is
therefore referred to as non-enzymatic glycosylation, or simply
What controls the process then?
Essentially, the reaction between glucose and protein is time
and concentration dependent. This means that the amount of
haemoglobin which forms HbA1c will depend on:
- The concentration of
glucose that the haemoglobin is exposed to
Not all cell types in the body require
insulin for the uptake of glucose. Red blood cells have
'insulin-independent' glucose transporters on their surface.
So if glucose levels in the plasma (the watery part of the
blood) are high, then glucose levels inside the red blood
cells will also be high. The higher the blood glucose level,
therefore, the more glycosylation of haemoglobin will occur.
- The length of time
that the haemoglobin is exposed to a given concentration of
The longer the blood glucose level is
high, the more glycosylation will occur.
Note, also, that this factor is
influenced by the age of the red blood cell - many cells in
our body are continually being broken down and replaced; the
average life span of a red blood cell is about 120 days. The
haemoglobin is continuously being glycated at a rate which
is proportional to the prevailing blood glucose level. At
any given time, there will be a mixture of old and new red
blood cells circulating in the bloodstream. Old cells will
have been exposed to recent, and not so recent, blood
glucose levels. New cells will only have been exposed to
recent blood glucose levels. So the more recent glycaemia
will have the largest influence on the overall HbA1c
reading. Indeed, it has been suggested that half of an HbA1c
value is attributable to the previous month, a further
quarter to the month before that, and the other quarter to
the two months before that.
Red blood cells in patients with
haemolytic anemia have a short lifetime and they are
therefore subject to less glycation; HbA1c levels in these
people are therefore lower.
The HbA1C test is currently
one of the best ways to check diabetes is under control; it is
the blood test that gets sent to the laboratory, and it is done
on the spot in some hospital clinics. Remember, the HbA1C is not
the same as the sugar level.
sugar/HbA1C numbers for good control are rather similar though:
sugar levels 5.5-6.5 mmols/l half an hour before meals versus 7%
Below are two examples of
people who have their HbA1c measured. One is poorly controlled,
one well controlled.
graph of sugar changes over 9 weeks. The sugar
(green line) changes between 7-12. This results
in an HbA1c level of
10% at the end of the 9 weeks (red
line). Poorly controlled.
the sugar changes
between 5-9. This results in an
HbA1c level of 7% at the end of the 9 weeks. Well
the HbA1C be measured?
levels fluctuate from minute to minute, hour to hour, and day to
day. Thus for hour to hour control, or day to day, a sugar level
is the best guide.
The HbA1C level changes slowly, over 10 weeks, so it can be used
as a 'quality control' test.
In diabetes sugars tend to rise more than usual, dropping with
exercise, rising after food, rising a lot more after sugary
food, and can make it hard to control.
If your diabetes
is controlled (an HbA1C lower than 7%), every 3-6 months but if the last reading is above 7% and you are in reasonable
health, you will need to achieve a lower level if possible, and
the next reading should be sooner.
This assumes you will make changes to improve your control.
There is no point in having your HbA1c measured if you are not
trying to achieve good control of your diabetes, although the
level does predict the likelihood of complications from your
Here's a chart as given by HbA1c and
Mean Blood Glucose comparison :
How should the HbA1C be measured?
methods including the measurement of Glycosylated Hemoglobin by Immunoturbidimetric
methods are comparatively unreliable. Such tests measure HbA
only and are neither accurate, nor specific
markers for HbA1c. Furthermore, the presence of an abnormal
Haemoglobin causes interference in the test, finally affecting
the result considerably. Accurate diagnosis of HbA1c
requires certain instruments. We have a wide range of instruments
for testing HbA1c.
: A reliable instrument for testing HbA1c. Micromat provides on the spot
and accurate results. The instrument is easy to operate and is
ideal for all clinicians, diabetologists and small labs. It
provides results in less than 5 minutes!!! Based on borate
affinity chromatography, there is no interference from abnormal
Haemoglobins and is very reliable. At Embee, we see
HbA1c using Micromat as the future of diabetes testing.
here to know more about this instrument.
: This is an ideal HbA1c monitoring device for the labs and
hospitals. The instrument is fast and accurate and is definitely
recommended for all the Pathological Labs who wish to conduct
here to know more about Diastat.
: The VARIANT™ Hemoglobin
Testing System provides automated diabetes monitoring, sickle
cell screening, beta-thalassemia testing and hemoglobinopathy
screening. The system is a perfectly ideal solution for major
labs who wish to perform a total, fast and accurate testing of
these. The Variant and Variant II are both state-of-the-art
systems and a must for every quality lab and hospital with
considerably large work load.
here to know more about Variant
for Variant II