We've come a long way from the days when urine strips only
displayed a result when your glucose levels were high enough to
spill over into your urine. But how accurate are today's blood
When you place your blood on a strip, the glucose in that sample
reacts with the chemicals in the strip setting up a small
electrical current, which the meter reads.
The more glucose that is in the sample the higher the current
and the higher the reading.
When you consider the delicate components in the strip, such as
the size of the strip and blood sample and the size of the meter,
it is a wonder of technology that readings can be as accurate as
In placing and keeping a blood glucose meter on the market,
meter makers must obey the International Organization for
These standards are enforced by Australia's own governing body
the Therapeutic Goods Administration (TGA), which from time to time
will recall these products when they don't meet certain
In 2013, new regulations for meter accuracy were agreed. These
standards were enforced in 2016. Project leader, Dr Alan Cariski,
comments, "More accurate glucose measurements will help patients to
better regulate their diabetes through more informed treatment
decisions that may affect, for example, dietary intake and
medication dose, especially insulin." (Lazarte, 2013)
What does this mean for you? In meters, readings greater
than 4.2 mmol/l, must have an accuracy of +-15 per cent for 99 per
cent of readings.
However, let's translate this to real life with a couple of
- Your blood glucose meter reading of 10.0mmol/l really may range
from 11.5 to 8.5mmol/l for 99 per cent of readings
- Your blood glucose meter reading of 4.2mmol/l really may range
from 4.8 to 3.6 mmol/l for 99 per cent of readings.
This also suggests that in the same blood drop if you used two
different meters, readings may differ by up to 30 per cent.
Many blood glucose meters have much better accuracy than this
minimum standard, and therefore are accurate enough for you to base
your decisions (Hannah L Sutheran, 2016).
Here are some facts to consider:
- Results of blood glucose will differ from each finger, body
site and from minute to minute. Blood flows constantly through our
skin and turnover is fast. Blood gets to different sites in your
body at different times and as blood travels glucose leaves. This
may be important if you are not always using the sides of your
fingers to check blood glucose. Blood glucose can rise and
fall quickly according to meal, insulin, exercise, etc.
- Readings differ with the level of red blood cells in your blood
(haematocrit). Some medications may change results as well.
- Maintenance of your meter is important. Clean and
calibrate (with control solution) as per your manufacturer's
- Check the expiry date of your strips. Ensure strips have
been kept at the conditions suggested by your manufacturer on the
packaging. Temperature, humidity and altitude will alter your
- As results will differ from meter to meter, base your blood
glucose decision on one meter. You may require another meter to
check ketones and keep a back-up meter.
- You cannot compare results from continuous glucose monitoring
or flash monitoring with blood glucose readings. The first
two monitoring systems read the glucose between cells in the skin
layer, which rises and falls slower than your blood glucose by 5-7
- Check your monitoring technique. If your reading doesn't
seem right go to our blood
glucose monitoring leaflet . What remains on your hands such as
food, moisturiser and hand sanitiser will affect your
- If you are unsure if a meter is working correctly, call the
manufacturer or you can contact Diabetes Queensland on 1300 136
Hannah L Sutheran, T. R. (2016, January 11). Technical and clinical
accuracy of three blood glucose meters: clinical impact assessment
usinf error grid analysis and insulin sliding scales. Journal of
Clinical Pathology, 899-905.
Lazarte, M. (2013, June 19). More accurate self-testing results
for diabetes patients with new ISO standard. Retrieved from
International Organization for Standardisation: