Glucose fasting, or the fasting plasma blood test, is a test doctors use to determine if a person is pre-diabetic or diabetic.
The Fasting Plasma Blood Test Explained
Anyone undergoing a fasting plasma glucose test (or FPG) must fast for twelve hours before the blood sample is taken; hence the name. The test works by detecting the amount of glucose left in a person’s blood twelve hours after they have eaten. This information tells your doctor how well and how fast your body processes glucose. A person who isn’t diabetic or pre-diabetic processes glucose much faster than a person who is, and will therefore have much lower blood glucose levels after a twelve hour fast.
If you’re having an FPG, your doctor will arrange for a blood sample to be taken, and ask you to fast for twelve hours beforehand. It’s imperative that you follow his instructions, otherwise, the results of your test will be off and your doctor may mistakenly think you’re diabetic or pre-diabetic.
Diabetes and Pre-diabetes
Diabetes is a metabolic disorder that occurs when your body can no longer produce enough insulin, the hormone responsible for regulating blood glucose levels. Pre-diabetes occurs in people who are developing type 2 diabetes, and it means that your body’s ability to produce insulin is on the decline. Your blood sugar levels will be higher than normal but not high enough to indicate diabetes.
Normal and Abnormal Blood Glucose Levels
If your blood glucose levels are normal, your fasting blood plasma test should show concentrations of less than 100 mg of glucose per deciliter of blood. If you’re pre-diabetic, you’ll have between 100 and 125 mg/dl of sugar in your blood. If you’re diabetic, you’ll have more than 125 mg/dl blood glucose concentration.