Validation

CPA and EFI both require that any new laboratory techniques, procedures, equipment or reagents be validated before being put into use. CPA defines validation as the confirmation through the provision of objective evidence, that the requirements for a specific intended use have been fulfilled. Validating a new laboratory technique involves answering the question ‘Is there evidence that this new technique does the job that it is intended to do’ and then producing the evidence to demonstrate this.

 

New laboratory techniques which involve the use of CE marked products and which are used as indicated by the suppliers do not need full validation as this is already undertaken by the supplier. The laboratory need only verify that the level of performance claimed by the supplier is achievable in the laboratory. In house techniques and techniques which make use of modified CE marked products need to have full validation.

 

Where an existing technique is being replaced, validation involves undertaking a systematic comparative evaluation of results obtained in parallel with the new and the existing standard techniques. In general, the new technique must yield results of equal or higher resolution or detail than the existing technique to be considered an adequate replacement. For the introduction of new techniques which are not replacing existing ones, validation involves testing the new techniques against know reference ranges. For quantitative techniques, this involves establishing the accuracy (closeness to reference value) and precision (reproducibility of results) of the new technique. For qualitative techniques this may be achieved by challenging the technique with known complex samples. An example in a new H&I laboratory would be challenging a HLA typing technique with rare types for instance.

 

Validation should always be undertaken in accordance with a document validation plan which describes the laboratory’s requirements of the new technique as well as lists what will be done and who will be involved. It also describes the responsibilities of all involved. It should also detail the acceptance criteria for determining whether or not the new technique is suitable for introduction into routine practice. The validation plan usually consists of clearly identifiable stages called the Design Qualification (DQ), the Installation Qualification (IQ), the Operational Qualification (OQ) and the Process Qualification (PQ). The DQ is a description of how the design of your laboratories processes will change to accommodate the new technique. For new equipment the IQ is usually provided by a supplier when they install a new piece of equipment and it verifies that the installation has taken place according to the manufacturer’s specifications. The IQ stage can be skipped for new techniques not involving installation of equipment. In the OQ stage the validation exercise demonstrates that the new technique operates as expected when tested as a standalone process. Finally in the PQ stage the validation seeks to demonstrate that the new technique performs satisfactorily when integrated into the laboratories processes.

 

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