Notifying investigators of IACUC protocol review outcomes in writing is:

Notifying investigators of IACUC protocol review outcomes in writing is required by the USDA Animal Welfare Act Regulations and PHS Policy, making it a fundamental aspect of compliance with these regulations. This requirement ensures that investigators are informed of the status of their protocols and any necessary modifications or approvals.

The procedural requirement for written notification serves both transparency and accountability in the research process, allowing investigators to understand the IACUC's assessment and to facilitate any required changes to align their research with ethical standards. This notification process helps maintain communication between the IACUC, which governs the animal research oversight, and the investigative teams conducting the research, thereby fostering an environment of ethical compliance and continuous improvement in animal welfare practices.

The other options mischaracterize the requirements. For instance, suggesting it is merely a common courtesy minimizes the importance of this written communication in upholding regulatory standards. Indicating that notification can only occur after minutes have been approved overlooks the critical need for timely feedback to investigators, which is vital for the continuation of research. Lastly, stating that notification is allowed only after the Institutional Official (IO) is notified does not align with the established protocols that emphasize direct communication with investigators to ensure compliance and address any concerns promptly.