"Study Plan" and "Study Protocol" are:

• A. Completely interchangeable OECD and U.S. regulatory terms
• B. Different terms with different meanings
• C. Only in OECD regulations
• D. Only in EPA regulations

Answer: (A)

In GLP practice, both terms refer to the document that outlines what will be studied, how the study will be designed, and how results will be analyzed, and regulators in both OECD and U.S. systems treat them as describing the same planning document before the study begins. That means they are used interchangeably across OECD guidelines and U.S. GLP regulations, so the two phrases effectively convey the same planning concept in regulatory context. The idea is that the plan/protocol sets the objectives, design, methods, and planned analyses, and inspectors look for the same information regardless of which label is used. Other options imply a difference in meaning or jurisdiction-specific usage, which isn’t how these terms are applied in practice.