Laboratories need to be accountable for the analytical results that they produce and this leads back to the procedures and process they have in place. ISO 17025 requires them to have policies to deal with customer complaints, with records being kept not only of these complaints but any subsequent investigations and corrective actions. In addition laboratories will need to have policies to deal with any aspect of non-conformance in testing or calibration even if it is not instigated by a customer complaint. Any changes that are necessary as a result of corrective action investigations must be documented as well as implemented. Since an evaluation of the significance of any nonconforming work needs to be made, recording and date stamping of any associated activities will help with this. In addition, ISO 17025 requires that laboratories should continually aim to improve the effectiveness of their management systems and this can be facilitated through audit results, and the analysis of data associated with corrective and preventive actions. Corrective action is, by definition, a reactive response to a problem. Laboratories are also required to have a preventative action policy, to allow the identification of improvements and potential sources of non-conformities. Any preventative action plans that are developed in this way must also be documented and monitored.