The 3Rs and methodologies for alternatives revisited

by Farah Moulvi, MSPH, PRIM&R Blog Squad member

PRIM&R is pleased to bring you more blog posts from the PRIM&R Blog Squad. The Blog Squad is composed of members who are devoted to blogging prior to, live from and after the PRIM&R’s conferences.

A recent article in PRIM&R’s Research Ethics Digest, titled, “The Role of Organizational Culture in Compliance With the Principles of the 3Rs,” made me stop to think about alternatives to the use of animals in research. As required by the Animal Welfare Act (AWA), the PHS Policy on Humane Care and Use of Laboratory Animals (PHS Policy), as endorsed by the Guide for the Care and Use of Laboratory Animals: Eighth Edition (Guide), and as executed by institutional animal care and use committees (IACUCs), research investigators must consider alternatives to procedures that may cause pain or distress to animals used in research. According to the US Government Principles for the Utilization and Care of Vertebrate Animals in Testing, Research, and Training, there are three central concepts, named by Russell and Burch in 1959, that need to be explored when considering alternatives: replacement, reduction, and refinement.

The replacement principle suggests substituting living animals with other living systems such as human and animal cell cultures, tissue cultures, non-living systems, or computer simulations when conducting research. Replacement also encourages researchers to substitute, when possible, a higher phylogenetic species, such as a vertebrate, with a lower, less sentient species, such as an invertebrate.

Reduction encourages scientists to use fewer overall animals to acquire the same scientific information.


Refinement refers to the modification or enhancement of procedures and techniques so as to minimize or eliminate pain or distress wherever possible.

The AWA requires that investigators demonstrate they have considered alternatives by providing a written documentation of the methods and resources used to determine the availability of alternatives. The USDA’s Animal Care Policy Manual provides guidance on the required written documentation, which includes performing a literature search within appropriate databases. The policy specifies that when conducting a database search the narrative must, at a minimum, include:

    1. The names of the databases searched;


    1. The date the search was performed;


    1. The period covered by the search; and


  1. The keywords and/or the search strategy used.

By performing the appropriate literature search, the investigator fulfills not only the requirement to search for alternatives to the use of animals and alternatives to potentially painful procedures, but also determines that the described research animal use does not duplicate previous or existing studies.

Because there are no universal IACUC protocol forms or templates for exploring alternative methods, I believe forms should include adequate information for the IACUC to determine whether the investigator has made a good-faith effort to demonstrate the presence or lack thereof of alternatives, and the reasons why he/she will or will not adopt them.


There are many resources available for investigators to explore alternatives in research, such as the USDA Animal Welfare Information Center (AWIC), which makes use of multiple database literature searching. Other resources include searchable databases such as AGRICOLA, TOXNET, the Johns Hopkins University Center for Alternatives to Animal testing (ALTWEB), the University of California’s Center for Alternatives, PubMed, and MEDLINE. Moreover, AWIC provides additional in-depth informational guides such as Tips for Searching for Alternatives to Animal Research and Testing and Worksheet and Instructions for Alternatives Literature Searching.


Whether you are a new investigator, veteran investigator, new IACUC member, an IACUC community member, or an IACUC coordinator, knowing these methodologies is critical. As an investigator, if you need assistance searching the literature for animal alternatives you can contact your IACUC chairperson, IACUC members, IACUC administrator, or your institutional veterinarian. Additionally, you can consult with AWIC , an information service specifically established to provide information about alternatives via e-mail.

What mechanism or processes has your organization developed to facilitate the IACUC’s review of this regulatory requirement? I would love to hear your thoughts. It’s your feedback that makes this a dialogue. If my blog makes you think, rethink, ask questions, or points you in a new direction—great! Please feel free to share.

Signing off from the electronic world for now, from the state of sun, sand, and surf (Florida, of course!) until the next blog…