Instructions:

1. Define your disease “problem” for which you wish to create a differential diagnosis.

2. Begin with the ten disease processes (y-axis). Navigate along each column until you intersect with the organ systems you have marked as being involved in your disease process.

3. Move on to the organ systems (x-axis). Move systematically through each organ system, reflecting on which systems may be involved in the pathophysiologic process you are investigating.

4. In each box that intersects, insert a disease that represents both the disease process and organ system.

   Ex: Your patient has 10/10 pain that is out of proportion in the abdomen. You first select the GI system, specifically the peritoneum. Next, you select vascular from the disease process. Where peritoneum and vascular intersect, you insert mesenteric ischemia, a vascular disease process involving the peritoneum.

5. Once each disease process has been identified, tailor your history, your physical examination, and your laboratory and imaging finds to rule in or rule out appropriately the listed disease. Through systematic addition and elimination via the necessary history, physical, and testing, your diagnosis should become clear!