Significant Changes to Approved Protocols

Significant Changes to Approved Protocols

Approved January 21, 1999   (Download) 

Background: Federal regulations require review and approval by the IACUC of significant changes in any activity involving the use of animals. However, defining what a “significant change” is has proven to be problematic. Broad interpretation by regulatory officials shows that deviations from approved protocols that seem insignificant to investigators as well as their institutional animal care and use committees have later been determined to be significant by regulatory officials investigating particular incidents. Guidance they provide indicates that it is better to confer beforehand with the IACUC or regulatory officials about what constitutes a significant change rather than after the fact.


Policy: A significant change includes any change or deviation in a protocol approved by the IACUC that:

  • results in increased mortality over levels that were either specified or presumed to occur when the protocol was originally reviewed.
  • results in increased morbidity or pain.
  • results in using a method of anesthesia or euthanasia different from that specified in the protocol.
  • results in using a different species.
  • results in using more animals than the number specified in the approved protocol.
  • results in a change in the overall aims or objectives of the study.
  • changes personnel performing animal use procedures.
  • results in changing a study,
    1. from not requiring surgery to one involving surgery;
    2. from requiring only minor surgery to major surgery;
    3. from requiring non-survival to survival surgery; or
    4. from requiring a single surgical procedure to one that requires multiple surgical procedures.

Principal investigators are responsible for insuring that members of their staffs who work with animals are familiar with relevant procedures and details specified in the protocols. In addition, supervision of work performed on animals must be adequate to insure that approved protocols are being followed and that significant changes are not implemented prior to IACUC approval.