Do you mean 5.1 mmol/litre? If so that's a reasonable reading in itself, but if you want to see how well your system handled your breakfast you'd need to test immediately before eating and two hours later. Lots of things affect our BG, not just food, and it would probably be hard to detect the food impact after five hours.My sugar reading is 5.1 after having breakfast and waiting 5 hours….. is this ok?