Eurachem/CITAC: new guide on evaluating measurement uncertainty from in-house precision and recovery data
On 16 March 2026 Eurachem announced the first edition of the Eurachem/CITAC Guide “Evaluation of measurement uncertainty from in-house precision and recovery data”. It describes how to evaluate the uncertainty of chemical measurements from intermediate precision and recovery data collected during method validation or verification of a standard method.
- The guide applies where in-house studies have provided intermediate precision data across the working range of the method and trueness information in the form of recovery — from independent reference materials or from spiking studies; detailed calculations cover the case where recovery deviates significantly from 100 %.
- According to Eurachem, key topics include modelling how uncertainty varies with concentration and handling divergent recovery values from different reference materials; a separate appendix deals with acceptable recovery intervals.
- Worked examples: nitrate in drinking water by ion chromatography (three variants) and total arsenic in sediments (three variants).
- The foreword recalls that the Nordtest handbook and ISO 11352 increase uncertainty instead of correcting for bias; the new guide offers tools for cases where an accurate value and reliable uncertainty are needed, e.g. for conformity assessment. The editor is Ricardo Bettencourt da Silva, and the working group includes a representative of Eurachem Poland (ISBN 978-972-9348-30-3).
Source: Eurachem — New guide: MU from precision and recovery data (16.03.2026)