A1C Accurate at Identifying Prediabetes

A routine blood test may be able to identify people with prediabetes[1] as well as the fasting plasma glucose (FPG) test[2], the method currently used by some doctors for screening, according to a recent study funded in part by the US Centers for Disease Control. An estimated 57 million adults in the United States have prediabetes (a condition in which blood glucose levels are elevated, but not enough for a diagnosis of diabetes) and the vast majority don’t know it.

The FPG test screens for diabetes by measuring the level of glucose in a person’s blood plasma after a period of fasting (not eating or drinking anything other than water). The test is performed after a person has fasted for at least 8 hours; people with a fasting plasma glucose level less than 126 mg/dl but greater than or equal to 100 mg/dl are classified as having prediabetes. Because the FPG test sometimes requires a second doctor’s visit for retesting, and because people often forget to arrive with an empty stomach, obtaining accurate results by the method can be difficult. The A1C test[3], currently used to check the level of blood glucose control over the previous 2–3 months in people with diabetes, only requires a single visit and is accurate regardless of whether a person has eaten prior to the visit. Based on blood test results from the 1,750 people included in the study, the A1C test is effective at pinpointing people who have prediabetes, and who are therefore at increased risk of developing Type 2 diabetes. (In 2010, the American Diabetes Association began recommending that the A1C test be used to diagnose Type 1 or Type 2 diabetes.)


According to Ronald T. Ackerman, MD, MPH, lead author of the study “If you have high blood pressure or heart disease, or multiple other risk factors such as obesity, are over the age of 45, had a past episode of diabetes during pregnancy, or have a family history of the disease, your physician can administer a simple blood test which will show if you are pre-diabetic. If you are pre-diabetic, losing as little as 10 to 15 pounds through diet and exercise can cut in half your chances of getting diabetes, greatly improving your health and lowering your need for health care.”

In a 2006 study, Dr. Ackermann suggested that it would be cost effective for Medicare to pay for diabetes prevention services starting at age 50 rather than waiting until age 65, when many people have already developed the condition. Since then, UnitedHealth Group, a nationwide carrier, has begun paying for a diabetes prevention program offered by the YMCA. The services are only covered, however, when a blood test has shown a person to have prediabetes.

To learn more about the research, read the article “Routine Blood Test May Identify People With Pre-Diabetes, Cutting Later Treatment Costs”[4] or see the study’s abstract[5] in the American Journal of Preventive Medicine. And for more information about the A1C test, click here[6].

  1. prediabetes: https://www.diabetesselfmanagement.com/Articles/Diabetes-Definitions/prediabetes/
  2. fasting plasma glucose (FPG) test: https://www.diabetesselfmanagement.com/Articles/Diabetes-Definitions/fasting_plasma_glucose_test/
  3. A1C test: https://www.diabetesselfmanagement.com/Articles/Diabetes-Definitions/Hba1c/
  4. “Routine Blood Test May Identify People With Pre-Diabetes, Cutting Later Treatment Costs”: http://www.sciencedaily.com/releases/2011/01/110106144745.htm
  5. the study’s abstract: http://www.ajpm-online.net/article/S0749-3797%2810%2900538-6/abstract
  6. click here: https://www.diabetesselfmanagement.com/Articles/Blood-Glucose-Monitoring/h_b_a_1_c/

Source URL: https://www.diabetesselfmanagement.com/blog/a1c-accurate-at-identifying-prediabetes/

Diane Fennell: Diane Fennell has been an editor at Diabetes Self-Management magazine since 2003. She is currently the Editorial Director. (Diane Fennell is not a medical professional.)

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