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The organisation of a test performance study (TPS) involves different steps that are mostly sequential, but some may be conducted simultaneously. This chapter details the following: the steps regarding the selection of the tests to be validated; the selection of the laboratories to participate in the TPS; the preparation of the materials and the dispatch of the samples; and the completion of the TPS (including the collection and analysis of the TPS results). The reader will be able to get the detailed information on how to define and plan timeline of the TPS, the appropriate number of samples (including replicates) and of laboratories that should be included in the TPS to ensure an appropriate statistical analysis, and how to perform basic analyses of the obtained data. In addition, this chapter covers the most important critical points which can endanger successful TPS organization providing the future TPS organisers in the field of plant health (but also in other similar fields) with the possibility to identify them in advance and carry-out successful TPS.

The recent COVID-19 pandemic highlighted the importance of rapid and reliable pathogen detection. In the field of plant health accurate and timely detection is a corner stone for successful pest control. Plant pests can be diagnosed with a variety of tests, which may be developed by commercial companies or research institutions. The reliability of diagnostic tests depends on the intended use of the tests, their performance characteristics and associated uncertainty obtained from validation studies and the experience of the laboratories. The performance characteristics of tests are obtained during a process called validation. Performance characteristics that are frequently used to characterise tests include: analytical sensitivity, analytical specificity (inclusivity and exclusivity), selectivity, repeatability and reproducibility. The validation process requires significant investment in terms of human and financial resources and can be conducted by a single diagnostic laboratory or through interlaboratory comparisons. The purpose of this book is to provide practical and technical guidance for the organisation of test performance studies (TPS), which are one type of interlaboratory comparison where the performance of (a) test(s) (is)are assessed by two or more laboratories. The major steps and challenges faced during the preparation, organisation and reporting of TPS are identified and can be used by organisers of future TPS not only in the field of plant pest detection, but also in other areas.

There are two types of interlaboratory comparison studies: proficiency tests, which aim at monitoring the proficiency of laboratories, and test performance studies (TPS), which aim at evaluating the performance of (a) specific test(s) and whether it (they) is (are) fit for purpose. This booklet covers only TPS organisation. A TPS is usually organised to monitor the performance of a newly developed test to detect and/or identify pests or to compare the performance of different tests. The results of TPS also provide information on how (a) test(s) perform(s) in different laboratories. This allows a better estimation of the accuracy and reproducibility of tests. Organising a TPS is a complex process that requires considerable effort from the organisers in terms of time, expertise, and finances. Therefore, the selection of e.g. pests and of participants are important steps which are described in this chapter It also discusses the minimum criteria that the TPS organiser should meet.