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Uncertainty of Measurement

Measurement Uncertainty

Measurement uncertainty (MU) is defined as a parameter, associated with the result of measurement that characterises the dispersion of the values that could reasonably be attributed to the measurand. By quantifying the possible spread of measurements an estimate of the confidence in the result may be obtained.

MU stems from imprecision as a result of random effects on the assay systems and so laboratories have to minimise the effects of this and acknowledge this uncertainty.

Calculation of Uncertainty within CDDFT

Within the examination process the laboratory can calculate the measurement of uncertainty that is associated with a measured analyte. We can use our internal and external quality performance checks to assess the individual uncertainties within the measurement system. For further information on our internal and external quality control systems please contact the laboratory.

The MU is the quantification of doubt, not error. The co-efficient of variation (CV%) or standard deviation (SD) can be considered as the combined uncertainty for results around the mean of a particular concentration of quality control material.

Working Example

For Haemoglobin, the Measurement Uncertainty in June 2017 (DMH) = 2.29%. Therefore, a Haemoglobin reported as 100g/L would have a Measurement Uncertainty of 97.7g/L - 102.3 g/L

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