popwess
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Within the forum many posting exist regarding the inaccuracy or inconsistency of blood glucose monitors, this posting therefore attempts to clarify what appears to be a fundamental misunderstanding about the readings obtained from these devices.
The I.S.O. Standard 15197 ( Standards and Statistics Used to Describe Blood Glucose Monitor Performance) states that:
95% of results obtained on samples ≤ 4.2 mmol/L shall be within ± 0.83 mmol
95% of results obtained on samples > 4.2 mmol/L shall be within ± 20%
Therefore a true reading of 4 mmol/L can be shown as 3.17 to 4.83 for up to 95% of readings.
A true reading of 7 mmol/L can be shown as 5.7 to 8.3 for up to 95% of readings.
The other 5% of readings are allowed to be outside these ranges and are regarded as clinically insignificant.
Whilst not all meters consistently provide readings that are this inaccurate it shows the potential for inaccuracy whilst still falling within the allowable limits.
In conclusion we should be aware that testing meters side by side, or even multiple tests on the same meter, can and will produce differing results and this is not a problem with the quality of the meter or strip being used but a problem with the standards by which these meters are judged..
The I.S.O. Standard 15197 ( Standards and Statistics Used to Describe Blood Glucose Monitor Performance) states that:
95% of results obtained on samples ≤ 4.2 mmol/L shall be within ± 0.83 mmol
95% of results obtained on samples > 4.2 mmol/L shall be within ± 20%
Therefore a true reading of 4 mmol/L can be shown as 3.17 to 4.83 for up to 95% of readings.
A true reading of 7 mmol/L can be shown as 5.7 to 8.3 for up to 95% of readings.
The other 5% of readings are allowed to be outside these ranges and are regarded as clinically insignificant.
Whilst not all meters consistently provide readings that are this inaccurate it shows the potential for inaccuracy whilst still falling within the allowable limits.
In conclusion we should be aware that testing meters side by side, or even multiple tests on the same meter, can and will produce differing results and this is not a problem with the quality of the meter or strip being used but a problem with the standards by which these meters are judged..
