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OGTT – impaired glucose tolerance — RACP Paediatrics MCQ

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ModerateEndocrineOGTT – impaired glucose toleranceRACP Paediatrics

A 12-year-old overweight child with acanthosis nigricans and a strong family history of type 2 diabetes is screened for diabetes. Fasting glucose is 5.8 mmol/L (normal <6.1). HbA1c is 41 mmol/mol (borderline). What further test would best identify impaired glucose tolerance?

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Correct answer: D — Oral glucose tolerance test

An oral glucose tolerance test (OGTT, 1.75 g/kg glucose max 75 g) with 2-hour glucose measurement is the most sensitive test for detecting impaired glucose tolerance (IGT) and early type 2 diabetes that may be missed by fasting glucose or HbA1c alone. IGT is defined as 2-hour glucose 7.8-11.0 mmol/L; diabetes ≥11.1 mmol/L.

Reference: RCH Melbourne – 2023 – T2DM CPG; ISPAD – 2022