Skip to main content




Classification of Protocols

The IACUC will use classification levels defined by the US Department of Agriculture based on anticipated pain and distress of proposed procedures.

  • Category B: No pain or distress. Animals kept for breeding or holding in a colony.
  • Category C: No more than momentary or slight pain or distress, no use of anesthetics.
  • Category D: Pain or distress relieved with anesthetics, analgesics and/or tranquilizer drugs or other methods for relieving pain or distress.
  • Category E: Pain or distress or potential pain or distress that is not relieved with anesthetics, analgesics and/or tranquilizer drugs or other methods for relieving pain or distress.

Protocols in Categories D and E

The United States Animal Welfare Act (AWA) regulations require that procedures involving animals avoid or minimize discomfort, distress and pain to the animals consistent with sound research design. Furthermore, principal investigators are required to consider alternatives to procedures that may cause more than momentary or slight pain or distress to animals, and to provide a written narrative description of methods and sources (e.g. the Animal Welfare Information Center (AWIC), used to determine that alternatives were not available. These requirements are explained in United States Department of Agriculture (USDA) policies 11 and 12.  The US PHS policy requires compliance with the AWA and the Guide for the Care and Use of Laboratory Animals.