Initiation, Starting and Completion Dates

Everything has a beginning and an end, and so have studies. This obvious truth does not seem to be the source of any problem, but when it comes to defining exactly these points, then difficulties arise. Again, these difficulties stem from the wide variety of study types performed under GLP, and the concomitant variety of time points that could define start or end of a study the importance for an exact definition of these time points is connected to the practical issue of when the GLP Principles have to be fully applied, since documentation before the start of a study may be less extensive than the one required once the study has begun. 

Four time points have been defined in the OECD Principles for start and end of a study. The so-called study initiation and study completion dates do not contain any ambiguities that could give rise to interpretation difficulties. The dates when the Study Director signs study plan and final report are unambiguous calendar dates, and they clearly mark the two time points between which a study has been conducted. However, more difficulties are encountered with the experimental starting and completion dates for themselves and for their connection with initiation and termination dates. 

While this is more of a semantic exercise, there are more important questions that can be raised in the context of these definitions. 

Consider the statements that an experiment starts at the date on which the first study specific data are collected. and is completed on the last date on which data are collected from the study. Could these dates not be defined in a more straightforward way Why, for instance, should the experimental starting date not be the date on which the test item is first applied to the test system, as it is stated in the GLP Regulations of the Environmental Protection Agency (40 CFR 160 and 792, resp., see Appendix II.III, page 329) And, conversely, why should the experimental completion date not be the date on which the test item is last applied to the test system The answer to these questions is, however, not as simple as it would seem at the first glimpse. It may be true that in the majority of cases, test item application can best define the experimental phase, i.e. its beginning and end. However, consider two situations, one of which has been already used to elucidate another point. 

Consider the two-year lysimeter study which has been described above, and in which there is just one application of the test item. Could this be the experimental starting as well as already the experimental completion date For the experimental starting date, this may well be correct but is it equally true for the completion date Certainly not, because the main experimental effort in such a study is the analytical determination of the test item concentration in the effluents and its distribution within the core of the lysimeter. Therefore, it is completely out of the question to set the experimental completion date as the date on which the test item has last been applied to the test system. 

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