As you have seen so far, coming up with the differential diagnosis is an important step, but there is still a lot that is uncertain. The physician is like the detective who has evidence pointing to a number of top suspects but who does not yet know which one actually committed the crime. Some more investigation must be done.

At this point, we order one or more tests to get information that we could not get in the interview or physical exam. These tests might require the use of technology and are typically more expensive than examining the patient manually. Also, some of these tests may have risks for the patient. At Lakeshore, we prefer to be selective and streamlined in the amount of testing we order; we try to order only the tests we need to make an accurate diagnosis without adding unnecessary costs and risks.

Critique of the Additional Tests
First, you will look carefully at the diagnoses Dr. Chang considered for testing and her reasons for wanting to investigate them. Then you will examine the tests she ordered and the reasons she gave for choosing them over other options. As before, I have attached a template we use for critiquing. You will be asked to think about whether you agree or disagree with the decisions Dr. Chang made. I won't go into a lot of detail about the issues you'll be considering, but here are a few examples of the kinds of questions you'll be asking about Dr. Chang's choice of tests:

• Is this test necessary to make a correct diagnosis and provide proper treatment to the patient?
• Will it give information that cannot be gathered by interview and exam alone?
• Is it worth the expense and potential risks?

Good luck. I'll check in with you again soon.

Sincerely,

Lee Mendoza, M.D.