Blood Sugar Monitoring: When to Check and Why

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Blood Sugar Monitoring: When to Check and Why

How often?

At least some studies have found that the more often people monitor their blood sugar with a conventional blood sugar meter, the better their glycosylated hemoglobin (HbA1c) levels. (The HbA1c test is a measure of blood sugar control over the previous two to three months.) Other studies have reported similar benefits for continuous monitoring, in which a sensor worn under the skin transmits glucose measurements every minute (or every few minutes) to a receiver. The GuardControl Trial, for example, found that participants with type 1 diabetes who used a continuous glucose monitor for three months experienced a 1-percentage-point drop in their HbA1c levels.

“In a perfect world, people with type 1 diabetes should monitor six or seven times a day,” says Om Ganda, MD, Senior Physician at Joslin Diabetes Center in Boston and Associate Clinical Professor of Medicine at Harvard Medical School. “However, that’s often impractical because of time and resources.”

If a person is newly diagnosed, starting a new treatment, or having trouble with blood sugar control, most insurance companies will pay for more strips than usual for the person to monitor more frequently, he notes. A person whose Type 1 diabetes is in stable control should monitor a minimum of four times a day.

For people whose Type 2 diabetes in good control, Dr. Ganda recommends monitoring twice a day. But, he notes, the majority of his patients with Type 2 diabetes are not in good control and should check more often. Unfortunately, health insurance companies often cover only one or two test strips a day for people with Type 2 diabetes, which many experts feel isn’t really enough to offer useful information. In some cases, insurance companies will cover more strips if a doctor writes a prescription for more, and some people choose to buy more strips on their own, out of pocket.


Dale notes, “Sure, test strips are expensive, but the price has not gone up in the past 20 years. At about $1 a strip, they are no more expensive than a bottle of water or a cup of coffee. It’s a matter of making the choice of where you want to spend your money.”

For those who are limited to one or two strips a day, one way to get more information about blood sugar patterns is to check on different days at different times.

“If your post-breakfast reading is usually in range, skip that reading and alternate monitoring before and after lunch and before and after dinner,” Dr. Ganda advises. “It’s important to check at different times throughout the day to see the bigger picture of what’s going on.”

Although these experts endorse frequent monitoring regardless of type of diabetes or method of treatment, a recent study made headlines by finding little value in monitoring for people with Type 2 diabetes who are not taking insulin. In the study, participants were split into three groups: A control group had their HbA1c levels measured every three months but was not asked to use a blood sugar meter unless their doctor considered it essential to their management. A less-intensive group was asked to record three blood sugar values daily on two days during the week (one fasting reading and the other two readings before meals or two hours after meals). Participants were also given blood sugar goals for before and after meals and advised to consider contacting their doctor if their readings were consistently high or low. A more-intensive group was also told to monitor their blood sugar levels at home and was given training and support in timing, interpreting, and using the results of their blood sugar checks. At the end of the year, both home-monitoring groups saw a slight reduction in HbA1c levels. However, the researchers note the results were statistically insignificant.

“This study has some limitations,” says Dr. Ganda. “First, participants were asked to monitor less than once a day, which is not frequent enough to provide the information needed to make appropriate changes to behavior or medication. By the end of the study, roughly half of the participants were monitoring less than twice a week. For home monitoring to help you reach your goals, you need to check more frequently, analyze the data, and make changes as necessary.”


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