The metrological traceability of measurement results is a key factor in ensuring that analysis results obtained at different facilities and using different equipment and methods are comparable. Traceability is also a condition for the mutual recognition of measurement results.
In order for the results to be comparable, all single measurement results must be linked to a commonly recognised measurement standard (SI measurement units) or stabile comparison material (chemistry) using calibration. In this way, the results are traceable and measurement uncertainty can be defined.
SI measurement system of units changed in May 2019.