Accurate pain assessment in laboratory animals is foundational to humane endpoint determination and effective analgesia, requiring validated species-specific tools that researchers can apply reliably.
Pain assessment is the foundation of humane laboratory animal welfare — without reliable identification of pain, analgesic decisions are guesswork and humane endpoints cannot be applied appropriately. The development and validation of grimace scales represents a genuine advance in laboratory animal welfare science, providing standardized, reliable tools that allow consistent pain assessment across different observers and institutions. Widespread implementation of validated pain assessment tools, combined with regular inter-observer reliability training, would dramatically improve the consistency and quality of pain recognition across the laboratory animal research enterprise.