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The HbA1c Tracker complements the Diabetes Chart
HbA1c conversion table by addressing the months leading up to a lab test. It
provides
- enhanced picture of daily glucose control
- estimate of HbA1c on an on-going basis
- tool for spotting
problems
- means of setting achievable improvement
goals
Importantly, the HbA1c Tracker is
comparatively easy
to understand and maintain. Instead of recording numbers, users enter
dots which are collected in a histogram.
Histograms: is a
picture worth a thousand numbers?
An HbA1c lab result reflects average glucose levels
over the previous two to three months. It corresponds to an average of
accurate and representative Self-Monitored Blood Glucose (SMBG) readings over the same period, and can be
estimated by determining that average. The easiest way of doing
this is to manage SMBG readings in the form of a histogram.
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A histogram simply takes
glucose readings and displays the relative frequency
with which they occur. It is an
accurate, yet intuitive and very visual tool. If properly sampled,
glucose readings cluster in central bars of the histogram. When this happens, the
tallest bar usually represents the average of the readings. It
also corresponds to an HbA1c estimate. With a little luck
HbA1c can be approximated merely by
glancing at the histogram. This is why we ask the question, "Is
a picture worth a thousand numbers?" The answer is
often "yes". Histograms and their visual
nature have additional benefits for diabetics. First, when a
predominant bar fails to occur, or when it occurs but does not
reflect the average, the shape of the histogram itself often
provides clues for troubleshooting. Second, the shape shows the tightness by which
glucose is
controlled. By becoming sensitive to histogram shape, a diabetic can better
appreciate how both good and poor glucose numbers affect their longer term blood sugar control.
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The
HbA1c Tracker Histograms
The HbA1c Tracker includes three histograms
for both plasma blood glucose readings and whole blood glucose
readings. For either type of reading the histograms vary in tightness
of glucose control, with class intervals arbitrarily set to round
steps in the HbA1c scale (1.0%, 0.5% and 0.2%).
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Plasma Blood Glucose
(Newer Home Glucose Meters) |
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Color code |
Glucose
control level |
Interval and
maximum predictive accuracy |
Covered
range |
| Blue |
Tight |
7
mg/dl, 0.2% HbA1c |
97-167
mg/dl, 4.9-6.87% HbA1c |
| Green |
Medium |
18
mg/dl, 0.5% HbA1c |
83-260
mg/dl,
4.5-9.47% HbA1c |
| Red |
Loose |
36
mg/dl, 1.0% HbA1c |
65-420
mg/dl,
4.0-13.97% HbA1c |
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Whole Blood Glucose
(Older Home Glucose Meters) |
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Color code |
Glucose
control level |
Interval and
maximum predictive accuracy |
Covered
range |
| Blue |
Tight |
6
mg/dl, 0.2% HbA1c |
87-146
mg/dl, 4.9-6.87% HbA1c |
| Green |
Medium |
15
mg/dl, 0.5% HbA1c |
75-224
mg/dl,
4.5-9.47% HbA1c |
| Red |
Loose |
30
mg/dl, 1.0% HbA1c |
60-359
mg/dl,
4.0-13.97% HbA1c |
Users are encouraged
to begin with the medium control level histogram and then move to the
tighter or looser chart if warranted by results.
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