A 43-year-old man comes to your office for the first time.

This patient’s lab results suggest impaired fasting glucose and an elevated A1c just below the threshold for diabetes. The gold standard to confirm diabetes in such intermediate cases is the 75 g oral glucose tolerance test (OGTT).

Toronto Notes 2023 – Endocrinology, “Diabetes Mellitus” Section:

“If A1c is in the 6.0–6.4% range or fasting glucose 6.1–6.9 mmol/L, a 75 g OGTT is recommended to establish the diagnosis of diabetes or confirm impaired glucose tolerance.”

MCCQE1 Objectives (Internal Medicine > 76-4: Diabetes):

“Candidates must correctly apply diabetes screening and diagnostic criteria and follow up abnormal results with appropriate confirmatory testing.”

Urine ACR (C) is useful in diagnosed diabetes, not for initial screening. TSH (A), capillary glucose testing (B), and exercise testing (E) are not indicated at this stage.

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