Is blood sugar of 7.8 high?

If your blood sugar levels are less than 140 mg/dL (7.8 mmol/L ) after two hours is considered healthy. 140 to 199 mg/dL (7.8 mmol/L and 11.0 mmol/L ) is diagnosed as prediabetes. 200 mg/dL (11.1 mmol/L ) or higher after two hours suggests diabetes.