Rosh Internal Medicine Boost Practice Exam

Which patient meets the criteria for a diabetes mellitus diagnosis?

1. A patient with a fasting plasma glucose of 125 mg/dL and a hemoglobin A1C of 6.0 percent

2. A patient with polyuria, blurry vision, and a random glucose of 200 mg/dL

3. An asymptomatic patient with a fasting glucose of 130 mg/dL (day 1) and 80 mg/dL (day 2)

4. An asymptomatic patient with a random glucose of 250 mg/dL

The correct answer is: A patient with polyuria, blurry vision, and a random glucose of 200 mg/dL

A diabetes mellitus diagnosis can be established through specific criteria set forth by the American Diabetes Association, which includes different methods of testing for hyperglycemia. In the scenario presented, a patient who exhibits polyuria, blurry vision, and a random glucose level of 200 mg/dL meets the diagnostic criteria for diabetes. The presence of symptoms such as polyuria and blurry vision, combined with a random plasma glucose measurement at or above 200 mg/dL, is definitive for the diagnosis of diabetes. This method does not require additional confirmatory testing because the symptoms alongside the glucose level clearly indicate a diagnosis. The other scenarios do not meet the necessary criteria for a diagnosis. For instance, the patient with a fasting plasma glucose of 125 mg/dL and a hemoglobin A1C of 6.0 percent illustrates a condition known as prediabetes, where neither measure by itself confirms diabetes. Additionally, the asymptomatic patient with a fasting glucose reading of 130 mg/dL on one day and 80 mg/dL the next does not provide a consistent basis for diagnosis, as normal fasting glucose levels are typically below 100 mg/dL, and this significant fluctuation creates uncertainty in diagnosing diabetes. Finally, while a random glucose level of 250