How to Read the Accuracy and Precision of a Blood Glucose Meter — The Truth behind the Numbers

Are the accuracy and precision the same?

Rukshan Pramoditha

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Image by stanias from Pixabay (slightly edited by the author)

Personal blood glucose meters do not provide exact measurements. Even lab-tested results can have a slight margin of error!

When reading your blood glucose value, you should consider both the accuracy and precision of the meter. Usually, they are mentioned in the user manual. Here is an example.

(Image by author)

The accuracy and precision are related not only to blood glucose meters but also to any measuring instrument.

What does accuracy mean in general?

Accuracy is the degree of closeness of a measurement to its true or reference value. In other words, it compares the measurement value with the true value.

Suppose the true value of a measurement is 89 and the equipment gives 90 as the measurement value. Because the measurement value is much closer to the true value, we can think the accuracy of the device is high at this time.

Suppose the true value of a measurement is 89 and the equipment gives 120 as the measurement value. Because the measurement value is far from the true value, we can think the accuracy of the device is low at this time.

Note: The accuracy of a measuring instrument can be determined by a single measurement!

What does precision mean in general?

Precision is the degree of closeness of a measurement to each other measurements under the same conditions. In other words, it compares repeated measurements under the same conditions. Precision is often referred to as repeatability.

Note: It needs several measurements to determine the precision of a measuring instrument.

Suppose an instrument gives 89, 87, 88, 90, and 92 values of repeated measurements under the same conditions, we can think the precision is high because each value is close to the other.

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Rukshan Pramoditha

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