Can the researcher review individually identifiable information to determine if there are enough patients for the protocol without the individual's authorization?

Generally, a researcher cannot review individually identifiable information without the individual's authorization, as this would typically violate privacy regulations like HIPAA in the United States. However, there are specific circumstances under which this may be permissible, such as if the review is part of preparing a research protocol and does not involve any identifiable data that could lead to the identification of individuals. Researchers should consult their institution's ethics guidelines and obtain necessary approvals, such as from an Institutional Review Board (IRB), to ensure compliance.