Joslin Answers Your Questions

Joslin Diabetes Center experts answer commonly asked questions about diabetes monitoring, treatment, self-care, meal planning, and more.
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Topic: Blood Glucose
Question: How often should I check my blood glucose?

Answer: First, it helps to understand why you should check your blood glucose. There are many reasons, but these are the most important:
  • To see what happens to your blood glucose levels when you eat certain foods
  • To see how activity affects your blood glucose levels
  • To see how pills or insulin affect your blood glucose levels

You also can get a general idea of whether your glucose control is staying the same, improving, or worsening. Most glucose meters available today can store your glucose results in their memory and are capable of displaying averages over the last seven to 30 days. Changes in these averages will likely reflect changes in your A1C—the blood test that reflects your body's average glucose over the last two to three months and that correlates with your chance of future complications. (Learn more about the A1C test.)

You might also check your blood glucose if you think it's too low or too high. Checking your blood glucose with a meter is one of the best ways for you and your healthcare team to see how well your diabetes is being managed.

Some people may need to check more often than others. That's why it is important to talk with your healthcare provider to find out what schedule is best for you. You can use the following Joslin Diabetes Center recommendations as a general guide when you discuss your own schedule with your provider:

Type of Diabetes When to Check Blood Glucose
Type 1 diabetes Check before each meal and at bedtime (at least four times a day).
Type 2 diabetes and taking insulin Check between two and four times a day; times will vary depending on your insulin regimen.
Type 2 diabetes and taking diabetes pills Check one or two times a day. If you check once, do so before you eat breakfast. If you check twice a day, check in the morning, and vary the time of the second check.
Type 2 diabetes with no medication Check before breakfast and two hours after a meal, alternating the mealtime; you may not need to check every day if your A1C is below 7 percent.

Occasionally checking blood glucose two to three hours after finishing a meal is helpful for people with either type 1 or type 2 diabetes. It also is a good idea to check your blood glucose more often than usual in the following situations:
  • If you're changing your meal plan
  • If you're changing your diabetes pills or insulin dose
  • When you think your blood glucose is low
  • When you are sick
  • If you are pregnant
  • Before and after physical activity
  • Before driving

No matter how often you check, keep a record of your blood glucose readings, and always bring the record to your diabetes appointments. This way, you can discuss your numbers with your healthcare provider or diabetes educator, and they can answer any questions you may have regarding your results. Also, having your numbers in a logbook can help your healthcare team decide if any changes may be needed in your diabetes treatment plan.

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