Prediabetes and Diabetes

According to the National Diabetes Information Clearinghouse, 79 million people in the United States have prediabetes. If you're one of them, you might be wondering why it matters—prediabetes isn't diabetes, is it?

While that is true, it is still very serious. Studies show that many people with prediabetes go on to develop diabetes within a course of about 10 years. In fact, most people who get type 2 diabetes had prediabetes first. Prediabetes is a warning sign that you're at high risk for progressing to diabetes. It's also serious in and of itself; those with prediabetes have a greater risk of developing cardiovascular disease than those without it.

So what exactly is prediabetes? It's a condition where your blood glucose levels are above normal, but not high enough for you to be diagnosed with diabetes. There are three tests that doctors do in order to determine whether you have diabetes (or prediabetes). These are:


This blood test, which is also called HbA1C, hemoglobin A1C or glycosylated hemoglobin, measures the percentage of sugar that is attached to your hemoglobin (a protein in your red blood cells). The higher the A1C, the higher your average blood sugar levels have been running over the past two or three months. A normal A1C is below 5.7 percent. An A1C between 5.7 percent and 6.4 percent suggests prediabetes. If your A1C is higher than 6.5, you have diabetes.


The FPGT, or fasting plasma glucose test, is a blood test that is done after you've been fasting overnight. It measures the sugar in your blood. A normal fasting glucose test is lower than 100 mg/dL. A result between 100 and 125 mg/dL is considered prediabetes. One that is above 126 mg/dL is considered to be indicative of diabetes.


The oral glucose tolerance test takes a little more time than the other two tests for diabetes. In this test, your blood is taken after an overnight fast and then again two hours after you drink a sugary drink. It's normal for blood sugar to rise after the drink. But normal blood sugar falls to below 140 mg/dL within 2 hours. If it is between 140 and 199 mg/dL, you have prediabetes. Anything 200 mg/dL or above is considered diabetes. 

Because prediabetes so often leads to diabetes—and because most of the time there are no noticeable symptoms—it's important to have one of these tests, especially if you are overweight and over age 45. For those people who are overweight and younger than 45, it may be a good idea, too, especially if there are other risk factors for diabetes, such as family history of diabetes, a sedentary lifestyle, high blood pressure, or elevated triglycerides.

If you do have prediabetes, your doctor may start you on a medication to help control your blood sugar. He or she will likely tell you that you need to lose weight and to exercise more. There is good reason to make the effort to change your life. Research shows that people with prediabetes can delay—and maybe even prevent—the onset of diabetes by making some lifestyle changes. Even losing 5-10 pounds and exercising for 30 minutes most days of the week can help.