Final answer:
When a sponsor discovers that an investigator used a device in a clinical investigation without obtaining informed consent from the subject, the regulatory affairs professional should report the protocol deviation to the IRB.
Step-by-step explanation:
When a sponsor discovers that an investigator used a device in a clinical investigation without obtaining informed consent from the subject, the regulatory affairs professional should report the protocol deviation to the IRB. Informed consent is a crucial ethical requirement in any clinical investigation, as it ensures that participants have full knowledge of the study and voluntarily agree to participate. Failing to obtain informed consent is a violation of research regulations and can have serious consequences.