Test Your Knowledge Answer #403

The patient had one randomly measured blood glucose value greater than 200 mg/dL (11.1 mmol/L), which indicates a need for further testing to establish the diagnosis of diabetes. A fasting blood glucose measurement is the preferred test to establish the diagnosis because of its ease of administration. A blood glucose level greater than 126 mg/dL (6.99 mmol/L) after 8 to 10 hours of fasting establishes the diagnosis of diabetes; the test should be repeated on another day to confirm the diagnosis. If a fasting blood glucose measurement indicates glucose intolerance in a high-risk patient such as this one (i.e., Hispanic, family history of diabetes, history of large babies, obesity), an oral blood glucose tolerance test should be performed. A 2-hour post-load value of 200 mg/dL (11.1 mmol/L) or greater on this test is considered positive for the diagnosis of diabetes. If the patient has glucose intolerance evident in blood glucose levels between the normal and diabetes ranges, education and counseling for lifestyle modifications should be offered because these strategies can delay or prevent progression to diabetes.

 

Fingerstick blood glucose measurement, although useful to monitor blood glucose levels, is unreliable for the purpose of diagnosis. Similarly, obtaining another random blood glucose measurement will not help establish the diagnosis. Neither a fingerstick test nor a hemoglobin A1C value is reliable to screen for or diagnose diabetes, and repeating these tests is not indicated. 

 

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