Is 108 A High Fasting Glucose Level?


Asked by Carol

I haven't been diagnosed with diabetes, but I have had lots of blood work over the years and my fasting glucose is always between 100 and 108 mg/dl. I thought anything under 110 was fine, but I just wanted to make sure?


According to the American Diabetes Association (ADA), a fasting blood glucose (FPG) level of 126 mg/dl or higher is evidence of diabetes. Levels below 100 mg/dl are considered normal.

Your fasting glucose of 108 puts it in the range between 100 mg/dl and 125 mg/dl. This range is considered indicative of insulin resistance and prediabetes.

If this were a one-time result, it would be smart to request a retest, to determine if the result was an error. Since you have consistently had a fasting blood sugar level above 100, however, it’s time to explore this further with your health care provider. Ask whether you should have additional tests to confirm prediabetes, and if prediabetes is confirmed, you’ll want to plan out steps you can take to help prevent it from progressing to type 2 diabetes.

The three key tests that can confirm prediabetes include:

Hemoglobin A1C (Hb A1C) Test: this test measures your average blood sugar levels over a several month period. A normal A1C level is less than 5.7 percent. Test results between 5.7 and 6.4 percent are evidence of insulin resistance and prediabetes. Levels of 6.5 percent and higher indicate diabetes.

Oral glucose tolerance test (OGTT): This test starts with a fasting plasma glucose blood test. You then drink a special sugary solution, and two hours later, you have another plasma glucose test. A normal result on the second test is a blood sugar level of less than 140 mg/dl at the two-hour point. Levels between 140 and 199 mg/dl show insulin resistance and prediabetes. Levels of 200 mg/dl and higher are evidence of diabetes.

Fasting blood glucose: Values between 100 mg/dl (5.6 mmol/l) and 125 mg/dl (6.9 mmol/L) indicate increased risk for diabetes (prediabetes).

If you have prediabetes, you should be checked for type 2 diabetes regularly. In addition, your health care provider can provide advice about how to prevent prediabetes from becoming type 2 diabetes. Some effective preventive approaches include:

  • Weight loss

  • Moderate exercise

  • Changes to your diet

  • Medications (as prescribed by a doctor), such as metformin, to help improve your insulin sensitivity

You should know: The answer above provides general health information that is not intended to replace medical advice or treatment recommendations from a qualified healthcare professional.

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