Verification or validation, that is the question
The latest revision of ISO 15189 standard in 2012 is now universally considered as the most important document for accreditation of medical laboratories. This standard is aimed to verify and validate examination procedures (EPs). Verification is “provision of objective evidence that a given item fulfils specified requirements”, while validation is “verification, where the specified requirements are adequate for the intended use”. When used without modification, validated EPs shall be verified, whilst non-standard methods, home brew methods, validated methods which have been modified or are being used outside their intended scope shall be validated before being introduced into clinical and laboratory practice. In order to fulfil the above requirements, three different approaches were used for: (I) verification of EPs already in use in laboratory; (II) verification of newly introduced EPs; (III) validation of EPs. For verification, at least two performance characteristics should be verified according to the intended use of specific EPs. Different operative flows are described for quantitative, qualitative and semi-quantitative methods. For validation procedure, a validation plan should be planned, including performance characteristics for specific EP, the experimental procedure and acceptability criterion. The final step of the validation process is production of a validation certificate. This is aimed to summarizing the validation process and defining the approval for being used in clinical practice. The proposed verification and validation procedures were actually fulfilling the ISO 15189 requirements during the accreditation audit. They can hence represent a model to follow for other medical laboratories.