Standard Adverse Effects and Early Removal Criteria

IACUC Policy: 036-08, Effective Date: 11/01/2009, Last Revision: 11/17/2023

Overview/Purpose

This policy provides standard early removal criteria (ERC) which apply to all research and teaching protocols at The Ohio State University unless exceptions have been scientifically justified and approved by the Institutional Animal Care and Use Committee (IACUC).

Early removal criteria are predetermined criteria, utilized as a basis for euthanasia prior to the planned study endpoint in an effort to minimize pain and or distress to the animals while enabling scientific goals to be met. Ideally, experimental endpoints occur with minimal or no adverse effects, pain, or distress to the animal. In some cases however, studies will result in pain/distress in order to accomplish the scientific objectives. Furthermore, the IACUC recognizes that experimentally induced or spontaneous clinical signs in animals may be unexpected or otherwise not specifically identified in the IACUC protocol. Consultation with the veterinary staff is expected when unanticipated adverse effects are observed.

Requirements

•  Investigators must ensure humane care of their research animals by checking all animals at least weekly to utilize ERC as listed in their protocol. Some animals will require more frequent oversight due to model/study endpoints and such oversight by the research team must be clearly outlined in the animal use protocol.
• Once an animal meets the ERC, the principal investigator is responsible for promptly (< 24 hrs.) initiating treatment as outlined in the protocol or euthanizing the animal. Alternatively, consultation with a veterinarian would be required to discuss treatment options.
• Experiments that necessitate unrelieved pain and/or distress as approved by the IACUC must be clearly identified to care staff at the cage level. This includes but is not limited to protocols using moribund as sole criteria for removal and death as an endpoint.
• The following criteria are considered standard ERC and apply across all protocols unless alternative criteria are identified and approved within the designated IACUC protocol:
  • Weight loss: i. Loss of 20% baseline body weight or compared to an age-matched control (for young growing animals)
  • Body Condition Score:
    • Rodents
      • Poor body condition scores ≤2 or ≥4
      • See Mouse Body Condition Score chart (Lab Anim Sci.1999;49(3):319-323).
      • See Rat Body Condition Score chart (J Am Assoc Lab Anim Sci. 2010 Mar; 49(2): 155–159).
    • Non-rodents
      • Poor body condition based on the species-specific reference scale as defined in the protocol.
  • Weakness/inability to obtain feed or water:
    • Inability or extreme reluctance to stand/ambulate for 24 hours.
  • Tumors:
    • Tumor size must not exceed 1.6 cm in any dimension in a mouse, or 3.6 cm dimension in a rat. When multiple tumors are present, tumor size must be based on cumulative longest dimensions. The IACUC will consider alternative endpoint criteria if justified and clearly described in your protocol.
    • Depending on the anatomic location, animals with tumors that interfere with normal function of vital organs (breathing, etc.) or impede the expression of normal activities (must be able to place all four feet on the ground and walk normally)
    • Ulceration greater than 2mm

Additional Information/Guidance

• Recognition and Alleviation of Pain in Laboratory Animals. 2009. Chapter 5. Humane Endpoints for Animals in Pain. Bookshelf_NBK32658.pdf (nih.gov)