Severity Classification of Laboratory Animal Procedures in Two Belgian Academic Institutions

SIMPLE SUMMARY: According to European regulations, the severity of the suffering of animals during animal experiments should be assessed. Regulatory documents and guidelines provide recommendations on how to approach this severity assessment; however, they are often not specific enough, resulting in inconsistencies between different institutes performing the same procedures. To overcome this, two Belgian academic institutions with a focus on biomedical research, collaborated to develop and align the severity classification for all procedures performed. This was performed based on the available literature and guidelines, as well as the professional judgment of the designated veterinarians, animal welfare bodies and animal ethics committees. Throughout the manuscript, we motivate which criteria were used to classify procedures or groups of procedures within a specific category. Our collaborative classification includes many procedures and disease models in a variety of animal species for which a severity classification was not reported so far, or the terms that assign them to a different severity were too vague. We believe this extensive list of procedures and the approach described in this paper could be of great value to other research institutions. ABSTRACT: According to the EU Directive 2010/63, all animal procedures must be classified as non-recovery, mild, moderate or severe. Several examples are included in the Directive to help in severity classification. Since the implementation of the Directive, different publications and guidelines have been disseminated on the topic. However, due to the large variety of disease models and animal procedures carried out in many different animal species, guidance on the severity classification of specific procedures or models is often lacking or not specific enough. The latter is especially the case in disease models where the level of pain, suffering, distress and lasting harm depends on the duration of the study (for progressive disease models) or the dosage given (for infectious or chemically induced disease models). This, in turn, may lead to inconsistencies in severity classification between countries, within countries and even within institutions. To overcome this, two Belgian academic institutions with a focus on biomedical research collaborated to develop a severity classification for all the procedures performed. This work started with listing all in-house procedures and assigning them to 16 (sub)categories. First, we determined which parameters, such as clinical signs, dosage or duration, were crucial for severity classification within a specific (sub)category. Next, a severity classification was assigned to the different procedures, which was based on professional judgment by the designated veterinarians, members of the animal welfare body (AWB) and institutional animal ethics committee (AEC), integrating the available literature and guidelines. During the classification process, the use of vague terminology, such as ‘minor impact’, was avoided as much as possible. Instead, well-defined cut-offs between severity levels were used. Furthermore, we sought to define common denominators to group procedures and to be able to classify new procedures more easily. Although the primary aim is to address prospective severity, this can also be used to assess actual severity. In summary, we developed a severity classification for all procedures performed in two academic, biomedical institutions. These include many procedures and disease models in a variety of animal species for which a severity classification was not reported so far, or the terms that assign them to a different severity were too vague.