Validation model of a laboratory-developed method for the ISO15189 accreditation: The example of salivary cortisol...

The ISO 15189:2012 describes the requirements for quality and competence, which are specific for all sectors of a medical laboratory. Laboratory-developed methods, standard methods used outside their intended scope and validated methods subsequently modified shall be validated. The main objective of validation of an examination procedure (EP) is to demonstrate its fitness-for-purpose. The aim of the present study is to illustrate a model to validate laboratory-developed methods in agreement with the ISO 15189:2012 requirement, through the example of salivary cortisol (sF) measurement by liquid chromatography tandem mass spectrometry (LC-MS/MS).

The proposed validation model for a laboratory developed method includes 6 steps: 1) analysis of available scientific documentation pertinent to specific EP; 2) evaluation of EP intended use; 3) identification of performance characteristics to evaluate; 4) definition of experimental procedure; 5) identification of acceptability criterion for results evaluation; 6) preparation of a validation plan; 7) production of a validation certificate.

sF is an EP sampled during the accreditation audit and resulted in compliance with the Standard. A structured procedure to certify that the achieved performance specifications are appropriate for the purpose of the test is therefore necessary.

A high competence is required for laboratory professionals in order to guarantee that the validated quality specifications have a positive impact on patients' management. The ISO 15189 accreditation is an important tool that allows demonstrating the value of a medical laboratory in the clinical context.