Which statement about diagnosis contributions is correct?

• A. The labs contribute 20%
• B. The exams contribute 60%
• C. The history accounts for 80%
• D. The history accounts for 50%

Answer: (C)

The main idea here is that what a patient tells you in the history carries the most weight in forming a diagnosis. By gathering details about the onset, progression, quality, timing, triggers, associated symptoms, past health, medications, and risk factors, you build a prioritized list of possible conditions and estimate how likely each is. That initial impression—the pretest probability—drives which questions you ask next, which tests you order, and how you interpret their results. In many medical education models, about 80% of diagnostic decision-making comes from the history, with the physical exam and investigations providing the remaining information to confirm or refine the diagnosis. So stating that the history accounts for 80% best captures how influential patient history is in guiding accurate diagnosis.