For gestational diabetes screening using the 75 g OGTT, which is the correct 2-hour threshold?

• A. 92 mg/dL
• B. 180 mg/dL
• C. 153 mg/dL
• D. 70 mg/dL

Answer: (C)

In the 75 g OGTT used for gestational diabetes screening, the 2-hour value is set at 153 mg/dL. If the 2-hour glucose reaches or exceeds this level (taken after the 75 g glucose load), gestational diabetes is diagnosed using the one-step criteria. The fasting threshold is 92 mg/dL and the 1-hour threshold is 180 mg/dL, so these time points have their own cutoffs. The number 70 mg/dL is not a threshold used for this test and would be unrelated to diagnosing gestational diabetes. The 2-hour threshold of 153 mg/dL reflects a risk-based cutoff identified to identify pregnancies with higher risk of adverse outcomes.