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Glucose is a sugar that circulates in the bloodstream, and it serves as the body’s main fuel source in producing energy. Blood sugar levels rise and fall throughout the course of a day, depending upon how much a person eats and his or her level of physical activity, so there is a range of acceptable glucose levels. A blood glucose test measures the milligrams of glucose per deciliter of blood, and this is abbreviated as mg/dL. Acceptable glucose levels range from 70-100 mg/dL during a fasting test, less than 200 mg/dL one hour after ingesting glucose and less than 140 mg/dL two hours after ingesting it.
Glycemia is a medical term for the presence of glucose in the blood. Too little glucose in the bloodstream results in an abnormal state called hypoglycemia, and too much is known as hyperglycemia. Both medical conditions are diagnosed by testing the level of glucose present in the blood. A fasting glucose test, in which the patient fasts for 10-12 hours, or a series of glucose tests conducted over several hours after the patient consumes a measured amount of glucose, yields a more accurate result than one random check of a person's blood sugar.
In a glucose tolerance test, the patient drinks a measured amount of glucose in a flavored solution. The acceptable glucose levels after a certain amount of time are known, and higher levels indicate impaired-glucose tolerance. This is commonly called pre-diabetes, because impaired glucose tolerance might develop into diabetes. A level of more than 200 mg/dL typically indicates diabetes. Although a slight rise in the average glucose level is normal during pregnancy because of hormonal changes, untreated diabetes during pregnancy can cause harm to both mother and baby.
Blood sugar fluctuates, so episodes of dangerously high or low levels of blood sugar might be missed. Another testing method called the A1c test is used to determine whether the glucose levels in the patient’s blood over a three-month period are in an acceptable range. This test is considered a more reliable indicator, because a single test on a given day does not measure how daily and hourly levels of glucose may fluctuate. A1c levels above 6.0 and below 4.3 are considered abnormal.
Glucose levels below 70mg/dL are called hypoglycemia. Although low blood sugar might not be as harmful to a person’s tissues and organs as high blood sugar, it can be a life-threatening event if the person loses consciousness when his or her blood sugar levels drop too low. It is important for patients to know what their acceptable glucose levels are to avoid the damaging effects of both high and low blood sugar.