Validation requirements of screening analytical methods based on scenario-specified applicability indicators

The performance of screening methods, as for any qualitative analytical method, is characterised by four parameters which define the success (sensitivity and specificity) and the prediction (predictive values) method capabilities regarding the objects/samples belonging to each of the classes or categories. But establishing a priori the critical values of these parameters to be used as validation requirements is not an easy task for stakeholders. In this tutorial, a new overall approach to carry out this task is described considering three application scenarios (conformity assessment, quality-oriented trade/marketing and profit-oriented trade/marketing). In addition, for greater ease, four applicability indicators (error index, saving index, penalty index and loss index) are proposed whose values can be intuitively assigned in order to determine the critical validation requirement of the method-performance parameters.