Urinalysis is routinely performed to assess kidney toxicity in regulatory studies. Urine sample collection, although traditionally considered non-invasive, raises animal welfare issues, as it usually requires single housing in grid-floor cages and/or catheterisation and often involves food or water restriction.
Moreover, it is not clear if urinalysis data are being used in practice and how often they play a role in decision-making. The quality of the data can be highly variable, for example samples are rarely collected from all animals, difficult to collect for certain species and easily contaminated. There are also other assessments that are considered more reliable and informative, for example kidney histopathology.
Previously, an expert working group in collaboration with the Laboratory Animal Science Association (LASA) highlighted the need to improve sample quality whilst refining urine collection methods to optimise animal welfare, and to collect data to assess if urinalysis is necessary in every study. We first presented these recommendations in 2007 but the issues identified then are still relevant. We have initiated a new project, bringing the expert communities together in a workshop to discuss the current challenges and identify opportunities for refinement.
NC3Rs/ACCP workshop
In October 2023, in collaboration with the Association for Comparative Clinical Pathology (ACCP), we hosted an in-person workshop on "Applying the 3Rs to urinalysis assessments in toxicity studies: refining procedures and adopting a case-by-case approach".
The aim of the workshop was to bring together experts in toxicology and clinical pathology from the pharmaceutical and agrochemical industries, and regulators, to discuss opportunities to apply the 3Rs to urinalysis assessments in toxicity studies.
The workshop included introductory talks illustrating various methods of urine collection and discussing the value of urinalysis in decision-making, followed by a series of industry case studies from the pharmaceutical and agrochemical sectors, and breakout sessions, to discuss the following topics:
Are urinalysis assessments necessary in every study or can we move towards a case-by-case approach?
When urinalysis is considered necessary, how can we refine urine collection?
Attendees were surveyed at the end of the workshop. 86% of attendees identified new 3Rs opportunities as a result of the workshop and all attendees considered there were opportunities to minimise and/or refine urinalysis collection periods and methods. You can view a high level summary of the survey results on X/Twitter (will require an account to view).
A publication is in preparation to summarise the workshop discussions and potential next steps. These include data-sharing to build the evidence base to support a case-driven approach – where urinalysis is only collected when scientifically justified – as opposed to a tick-box approach to satisfy regulatory requirements.
