Validation of Molecular Diagnostic Assays and Quality Assurance and Control in the Veterinary Laboratory

Abstract

This chapter describes the process of validating in-house molecular assays although the principles described are equally relevant to all diagnostic assays. The best practice principles described below are based on the In Vitro Diagnostic Medical Devices Directive (IVDD) and associated documentation. Although compliance with these regulations is not required for diagnostic reagents used on animals, the principles are equally relevant to validation of all diagnostic assays, whatever their purpose.

Glossary of Terms

Fitness for purpose 

“Fit for purpose” means that the kit has to be validated to such a level to show that the kit’s results can be interpreted to have a defined meaning in terms of diagnosis or another biological property being examined (see www.oie.int/our-scientific-expertise/certification-of-diagnostic-tests/the-register-of-diagnostic-tests).

In-house 

Any assay developed within the laboratory or commercial assay which is modified or used off label, i.e., used in a different way, for a different purpose or using a different sample type from that recommended by the manufacturer.

Validation 

Confirmation, through the provision of objective evidence, that the requirements for a specific intended use or application have been fulfilled [ISO 9000:2000]. Validation is normally performed by the manufacturer (whether commercial or in-house).

Verification 

Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled [ISO 9000:2000]. Verification is normally performed by the user prior to introduction of a validated assay to determine if the assay achieves the required specification in their hands.