A. Many healthcare profes-
sionals believe that the result
that you get with your meter
should fall within 15% to
20% of the result obtained
on laboratory equipment
when whole blood is tested.
5
However, there are a number
of reasons why the blood
glucose result from your
meter may vary even more
than 20% from a labora-
tory result.
6
One of the most common
reasons is that laboratories use
only the serum or plasma
portion of the blood for
glucose testing, while home
monitors use a sample of
whole blood. Whole blood
results are approximately
10% –12% lower than serum
or plasma results from the
same blood sample (at average
hematocrit levels 41%–45%).
To adjust for this difference,
divide the laboratory value by
112% or 1.12.
7
Example:
• Let’s assume your
lab (plasma) result is
150 mg/dL.
• 150 divided by 1.12 =
134 mg/dL.
• Compare your meter result
to 134 mg/dL.
You can still expect a varia-
tion from this number based
on other factors, noted below.
There is a difference in the
glucose levels of venous blood
(usually drawn from a vein in
your arm) and capillary blood
(blood from a fingerstick).
After a meal, the glucose
levels in the capillaries may
be 20 –70 mg/dL higher than
the levels in venous blood.
6
If your lab test is taken while
you are in the fasting state
(before breakfast), this differ-
ence will be minimal
(2–5 mg/dL).
7
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