According to the Animal Welfare Act, the principal investigator is required to provide a written narrative to his or her IACUC stating that alternatives to painful procedures have been explored and are not available. Animal Care Policy #12 of the USDA Animal Care Resource Guide, "Written Narrative for Alternatives to Painful Procedures" states:
When a database search is the primary means of meeting this requirement, the narrative must, as a minimum, include:
Regardless of the alternatives source(s) used, the written narrative should include adequate information for the IACUC to assess that a reasonable and good faith effort was made to determine the availability of alternatives or alternative methods.
- the names of the databases searched;
- the date the search was performed;
- the period covered by the search; and
- the key words and/or the search strategy used.
It will help your report to keep a log of the above four points for each search performed. @LTWEB provides a link to a worksheet that may be helpful when thinking about creating your narrative.