In eCerto: Statistical Tests for the Production of Reference Materials

Trueness

The trueness of an analytical method, which describes the consistency between an analytical result and a reference value, can be tested in different ways. Possible procedures are analysis of a reference material, comparison to a (different) reference method or analysis of samples of specified concentration(s).

For the latter, $n \le 6$ independent samples should be prepared and analyzed at 3 different concentration levels $j$ covering the working range. For each level, the recovery should be calculated by comparison with the reference value as $$R = \frac{\overline{x_j}}{x_{r,j}} \times 100\%$$ where $\overline{x_j}$ is the mean value of all replicates at level $j$ and $x_{r,j}$ is the according reference value. Recovery values $80\% \le R \le 120\%$ are acceptable.

Currently, eCerto only allows to copy/paste a statement regarding the recovery calculations which will be stored together with the other data and incorporated in the report.