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Different Fasting Fingerstick Glucose Results



I can check my glucose at work with a fingerstick. Yesterday it was 110, fasting. This morning it was 142, asting. Checked it again about 20 minutes later and it was 116. I am sure I`m prediabetic but what was the 142 reading?


Let's start by reviewing current blood sugar guidelines: a normal fasting blood sugar does not go over 99. Diabetes is diagnosed when a fasting blood sugar is 126 or higher on at least 2 different days, or a random (anytime) blood sugar of 200 or higher. Prediabetes is a fasting blood sugar from 100 to 125.

Two things to consider with that fasting blood sugar of 142: first, although it was greater than 125, it was a single reading. Two, blood glucose meters are home testing devices. They give a good day-to-day account of what blood sugars are doing but for diagnosing both prediabetes and diabetes, a venous draw from the lab would be recommended since it is considered to have the highest degree of accuracy. So we can't say you have diabetes because you had one instance of a fasting sugar of 142. Your other fasting readings (110, 116), are suspicious of prediabetes. Your health care provider could provide you with a referral to the lab for both a fasting blood sugar and a hemoglobin A1C test to see if, in fact, you have prediabetes or diabetes.

What is a hemoglobin A1C and why would you also want this done? This blood test is a collective measure of what all your blood sugar readings have been for the previous 3 months, not just a single reading. It is a measure of what percentage of your red blood cells are carrying sugar. The higher the blood sugar, the more of the red blood cells that have sugar 'stuck' to them. A normal hemoglobin A1C should be less than 6%.

The treatment for prediabetes focuses on healthy weight, diet, and increasing physical activity. If a person with prediabetes is overweight even a weight loss of as little as 7-10% will usually bring their blood sugars to an acceptable range. The diet is the same recommended in diabetes: moderate amount of carbohydrates, (emphasizing whole grains, fresh fruits and vegetables and low-fat dairy), lean protein and heart-healthy fats, eating regular meals daily with a consistent amount of carbohydrate meal-to-meal. 150 minutes of physical activity above-and-beyond what you currently do per week will also help the cells absorb blood sugar resulting in better blood sugar readings. This works out to as little as 30 minutes/day for five days/week, and yes, walking is excellent exercise! Be sure to get your health care provider's ok before beginning any exercise program.

Your health care provider can discuss your concerns, further testing options and help you to develop a treatment plan. A referral to a certified diabetes educator is also highly recommended.

For more information:

Go to the Diabetes health topic, where you can:

Response by:

Margaret G Doyle, RD, LD, CDE Margaret G Doyle, RD, LD, CDE
Case Western Reserve University