Refinement of animal use--assessment and alleviation of pain and distress.

The refinement of experimental techniques represents an important opportunity to improve the welfare of laboratory animals. Objective methods for the assessment of pain and distress in animals are needed before procedures that are claimed to be refinements can be evaluated. The methods currently used for assessment of pain and distress are unsatisfactory, and are often based on uncritical anthropomorphic assumptions. Future developments may enable the establishment of well validated clinical scoring systems, or identification of biochemical or physiological indices of pain or distress. If reliable methods of pain assessment can be developed, then a critical evaluation of the methods available for the alleviation of pain and distress can be undertaken. This article reviews methods of clinical pain assessment in animals, with reference to the techniques used in man. Techniques for pain alleviation are briefly reviewed.