Patient Self Testing The level of blood sugar or blood glucose is measured accurately six to eight hours after the last meal. This is why it is commonly determined in the morning, before breakfast. The normal ranges for a healthy individual lie between 70 and 100 milligrams per deciliter. inr levels After having a meal, the sugar level rises. The maximum range shouldn't exceed the 135-140 mark for a healthy person. With diabetic patients, blood sugars can either be too low or very high, conditions that are called hypoglycemia and hyperglycemia. Extreme values lead to serious medical issues.