Every result generated by a laboratory has an uncertainty associated with that value. The way a sample is collected and handled, as well as the analytical instrumentation and supplies used to test the sample, all have the potential to impact the uncertainty of a measured value.

Measurement uncertainty can be expressed in multiple ways. Gateway Labs calculates an expanded measurement uncertainty value for each quantitative analysis. This is calculated over not less than 24 replicates and is calculated at a 95% confidence level.

The higher a measurement uncertainty value, the less confident you can be that the result is the "true value." The lower the measurement uncertainty, the more confident you can be the result is near the true value.

The measurement uncertainty of the analysis can impact pass/fail decisions being made on CoAs. A sample tested near the reporting limit on a method with higher measurement uncertainties could result in false positive or false negative results.

Decision rules on passing or failing an analysis are set by the OMMA. Gateway Labs follows the OMMA thresholds to determine if a sample passes or fails an analysis for CoA reporting.