Blood sugar is a measure of the glucose concentration in the bloodstream in units of milligrams per deciliter or millimoles per liter, according to Medical News Today. Blood sugar numbers consistently higher than the average indicate hyperglycemia, often associated with diabetes, and numbers below the average indicate hypoglycemia.
Prior to the first meal of the day, blood sugar levels are typically between 70 and 130 milligrams per deciliter for healthy individuals and less than 180 milligrams per deciliter two hours after a meal, according to Diabetes Self-Management. Typical blood glucose levels vary from person to person, and the numbers may mean different things for different people.
For example, an individual with a blood glucose number that is higher than normal first thing in the morning and decreases during the day may have a malfunctioning liver that is continuously sending glucose into the bloodstream during the night, reports Diabetes Self-Management. Blood glucose levels that remain high all day typically indicate type 2 diabetes, and a sudden change in blood glucose levels in diabetes patients may mean infection.
Blood glucose numbers over 180 milligrams per deciliter two hours after eating in individuals with diabetes typically mean the ratio of insulin to carbohydrates consumed is too small and the individual should reduce the amount of carbohydrates he consumes, according to BD. A blood glucose number above 150 milligrams per deciliter directly before bedtime generally means an individual needs to eat less super or consume fewer late-night snacks.