Is it diabetic to have fasting blood sugar at 7.4mmol/l and 2-hour postprandial blood sugar at 5.5mmol/l?

Answer 1

Not necessarily; even though a fasting blood glucose level (BGL) over about 6 mmol/L is abnormal, a 2h postprandial BGL of 5.5 is normal (anything below 7.8 2h post-prandially is considered within normal limits). However, look at alimentary hypoglycemia when [fasting BGL] > [2h postprandial BGL].

Answer 2

1

Answer 3

Post prandial lowering of blood glucose is called "dumping syndrome" and occurs as a delayed complication of Gastrojejunostomy a surgical procedure for duodenal ulcer.
Other reasons can be that the individual has taken blood glucose lowering drugs or insulin after fasting sample is collected.