Characterization of a measurement method: key stage in the validation process

To validate is to provide evidence that the method of measurement or analysis meets the particular requirements for a specific intended use (see § 5.4 of NF ISO/CEI 17025 "General requirements for the competence of testing and calibration laboratories"). Apart from standardized methods (or methods defined by consensus by a profession) which are considered validated by accreditation bodies when used in their field of application, other methods (adapted standardized methods, methods developed in-house, etc.) must have a validation file providing evidence that their performance matches the needs formulated by a customer (internal or external). In fact, the need may be to respond to a one-off request from a customer, or to offer a new service.

Analysis of the candidate measurement method (measurement process in the broadest sense) and the customer's requirements results in one or more characteristics to be studied. These characteristics (trueness, repeatability, reproducibility, limit of quantification, linearity, etc.) are part of the step called "intralaboratory characterization" in the method validation process.

This document simply presents the tools used to quantify or verify these performance characteristics within the laboratory. It does not deal with the performance characteristics of the interlaboratory test method developed in the NF ISO 5725 series of standards .