Children's Hospital


Why Your Healthcare Provider Tests Your Blood Sugar

If you don’t have diabetes, and your doctor orders a blood sugar test, what is he or she checking? In adults, a screening blood sugar test is generally used to see whether blood sugar is too high. Often adults with raised blood sugar don't have obvious symptoms of diabetes or prediabetes. Finding and treating type 2 diabetes early is important to prevent problems that it can cause. According to 2011 statistics from the CDC, about 19 million people have been diagnosed with diabetes. An additional 7 million Americans have diabetes but have not been diagnosed. At least 79 million people in the U.S. ages 20 and older have prediabetes. In adults, type 2 diabetes makes up the most of the diagnosed cases.

Type 2 on the rise

Type 2 diabetes is on the increase in the U.S. This rise can be controlled if more people pay attention to lifestyle choices. Americans eat too much and exercise too little. Some long-term damage to the body, especially the heart and circulatory system, may already be occurring during prediabetes. People with prediabetes are at high risk of developing type 2 diabetes. Studies have shown that people with prediabetes can put off the development of type 2 diabetes by doing several things. They can make changes in their diet, exercise more, and lose weight. 

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, made by your pancreas, isn't used properly. Insulin allows your body to use sugar and other food for energy. Blood sugar rises when you don't have enough insulin. It also rises when your body's cells are unable to use what is there.

In type 2 diabetes, your pancreas either does not make enough insulin or your body’s cells aren’t properly using the insulin. This is called insulin resistance. When blood sugar goes up again and again, the risk of heart attack and stroke increase by up to 4 times. It also greatly raises the risk for kidney disease. You are also at risk for blindness, amputation because of poor circulation, and other disorders.

Type 2 diabetes is usually diagnosed later in life. But in an alarming trend, many teens are being diagnosed with it. This was almost unheard of 20 years ago. This is thought to be directly related to being extremely overweight, having a poor diet, and a lack of exercise. The American Diabetes Association (ADA) recommends type 2 diabetes screening for children and teens who are overweight and have at least 2 of these risk factors: a family history of diabetes, being in a high-risk ethnic group, or having their healthcare provider see signs of insulin resistance.

It's always best to find diabetes before symptoms begin. But watch for these symptoms: extreme tiredness, intense thirst, frequent urination, sores that don't heal, accidental weight loss, and on-and-off blurry vision.

According to the U.S. Preventive Services Task Force, adults who are 40 to 70 years old and are overweight or obese should get screened every 3 years. If you have other risk factors for diabetes, you may need screening tests more often.

Risk factors

Risk factors for type 2 diabetes are:

  • Being older than 45 years

  • Being overweight 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 ("good') cholesterol of less than 35 mg/dL and/or a triglyceride level of 250 mg/dL or higher

  • Getting little exercise

  • High-risk race/ethnicity (African American, Alaska Native, Hispanic American, American Indian, Asian American, or Pacific Islander)

  • Blood sugar test in the past that was high

  • Having had diabetes during pregnancy or giving birth to a baby weighing more than 9 pounds at birth

  • Having polycystic ovarian syndrome

  • Having a history of heart disease

Diagnosing diabetes

The ADA now recommends the A1C test to help diagnose prediabetes and diabetes. The A1C estimates the average blood glucose levels over the previous 3-month period. An A1C level of around 5% is considered normal. An A1C of 6.5% or above shows diabetes.

The A1C test is not more accurate than the fasting plasma glucose test and the 2-hour oral glucose tolerance test. The difference is the AIC test does not require fasting, so it can be measured at any time of the day. Experts hope the convenience of A1C will result in more testing for people who are at risk for diabetes or prediabetes. This would help reduce the number of people with undiagnosed diabetes in the U.S.

Online Medical Reviewer: Holloway, Beth, RN, MEd
Online Medical Reviewer: Turley, Ray, BSN, MSN
Last Review Date: 2/3/2015
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