Why Your Doctor Tests Your Blood Sugar

If you don’t have diabetes, and your doctor orders a blood sugar test, what is he or she is checking? In adults, a screening blood sugar test is generally used to determine if your blood sugar is too high. For adults, having an elevated blood sugar usually will not give you symptoms and that may indicate a pending or current problem with type 2 diabetes. Catching and treating type 2 diabetes early is important to prevent complications of diabetes. Nearly 24 million Americans have diabetes, and almost 6 million don't know they have it, according to 2005 statistics from the Centers for Disease Control and Prevention (CDC).

According to the American Diabetes Association (ADA), if you're 45 or older and you don’t have risk factors for diabetes, you should get screened every three years. If you have risk factors for diabetes, you may need screening tests more often. If you're under 45, you don't need routine screening unless you are over weight or obese, and have another of the risk factors for diabetes.

Risk factors for type 2 diabetes are:

  • Being older than 45

  • Being over weight or obese (body mass index of 25 or higher)

  • Having parents or siblings who have diabetes

  • High blood pressure (140/90 mmHg or higher in adults)

  • HDL cholesterol of less than 35 mg/dL and/or a triglyceride level of 250 mg/dL or higher

  • A sedentary lifestyle

  • Race/ethnicity (African American, Alaska Native, Hispanic American, Native American, Asian American, or Pacific Islander)

  • Previously elevated blood sugar test

  • Having diabetes during pregnancy or having a baby weighing more than nine pounds at birth

  • Having polycystic ovary syndrome

  • Having a history of cardiovascular disease

The ADA recommends the fasting plasma glucose (FPG) test to determine if blood sugar is elevated because it easier, faster to perform, more convenient, acceptable to patients, and less expensive than other tests. (Fasting means having no food or beverages, other than water, for at least eight hours before the test.) If there are no other risk factors for diabetes, a FPG of less than 100 mg/dL is considered normal. An FPG equal to 100 or less than 126 is called impaired fasting glucose and may indicate a condition called pre-diabetes. Pre-diabetes means there is a high risk for development of diabetes in the future. If the FPG is below 126 and there are reasons to suspect diabetes, or if the FPG is equal to or greater than 126 mg/dL, further testing is necessary to determine if a person has type 2 diabetes. Medications can influence the test by artificially lowering or raising blood sugar.

There's an epidemic of type 2 diabetes in America. That epidemic can be controlled if more people begin to pay attention to lifestyle issues. As a society, we eat too much and we exercise too little. The CDC estimates that at least 57 million people in the United States age 20 or older had pre-diabetes in 2007. Some long-term damage to the body, especially the heart and circulatory system, may already be occurring during pre-diabetes. People with pre-diabetes face a great risk for developing type 2 diabetes. The nationwide Diabetes Prevention Program study showed that people found to have pre-diabetes could prevent the development of type 2 diabetes by making changes in their diet and increasing their level of physical activity.

Many people don't know what type 2 diabetes is or why doctors are interested in their blood sugar levels. In diabetes, the hormone insulin, secreted by your pancreas, isn't used properly. Insulin lets your body use sugar, starches and other food for energy. When there isn't enough insulin or your body's cells are unable to use what is there, blood sugar rises. In type 2 diabetes, your pancreas either does not secrete enough insulin or insulin isn't used properly by the body’s cells (called insulin resistance). Insulin lets your body use glucose, a form of sugar, for energy by transporting glucose into the cells. When there isn't enough insulin or your body's cells are unable to use glucose, blood sugar rises.

When blood sugar is consistently elevated, the risk of heart attack and stroke increase by up to four times. It also greatly raises the risk of kidney disease, along with leg amputation from poor circulation, blindness, and other maladies.

Type 2 diabetes is usually diagnosed later in life. In an alarming trend, we're diagnosing many teens with this type of diabetes--something almost unheard of 20 years ago. This is thought to be directly related to obesity, poor diet, and lack of exercise.

The ADA recommends type 2 diabetes screening for children and teens who are overweight and have at least two of these risk factors: a family history of diabetes, in a high-risk ethnic group, or have signs of insulin resistance.

It's always best to catch diabetes before symptoms begin. But watch for these symptoms: fatigue, thirst, frequent urination, sores that don't heal, weight loss, and intermittent blurry vision.

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