- Medication: Some classes of oral drugs can cause hypoglycemia or low blood sugar, so you may need to test more often. "Generally, anyone who takes insulin should test several times a day as well as individuals who take sulfonylureas or meglitinides," says Nadine Uplinger, a spokesperson for the American Association of Diabetes Educators and director of the Gutman Diabetes Institute at the Albert Einstein Healthcare Network in Philadelphia.
- Changes: If you've just been diagnosed with diabetes, started on a new medication, added a new type of food, or recently changed some other factor (for example, you have gained or lost weight, or are exercising more or less often), then you should test more frequently. "Individuals who are changing their treatment regimen should test several times a day," Uplinger says.
- Blood sugar at diagnosis: People who have high blood-sugar levels when they're diagnosed will need to test more often as well. According to the American Diabetes Association, your blood-sugar level before a meal should be in the range of 70 mg/dL to 130 mg/dL, and after a meal it should be less than 180 mg/dL. A person whose sugars are in the 500s when they're first diagnosed will have to test more often than someone whose sugars were 180, says Diana Berger, MD, a diabetes medical specialist at the Diabetes Prevention and Control Program at the New York City Department of Health and Mental Hygiene.
- History of blood-sugar control: The American Diabetes Association recommends that patients who are meeting treatment goals get hemoglobin A1C tests twice a year at their doctor's office. For patients whose therapy has changed or who are not meeting treatment goals, the ADA recommends hemoglobin A1C testing four times a year. If the hemoglobin A1C test result is less than 7%, suggesting relatively good long-term blood-sugar control, you may be able to test your blood sugar less often (if you're not on insulin). Many doctors recommend testing twice a day at varying times, such as before and after breakfast, lunch, and dinner, or at bedtime. "Two tests a day over the course of a month can really characterize the glucose profile of a patient," says Stuart Weiss, MD, of New York University School of Medicine, in New York City.
What you can afford: You can usually get a blood glucose monitor free or insurance may cover it. It's the strips that can be expensive. At a dollar a pop, testing four times a day could cost you roughly $120 a month. Don't hesitate to tell your doctor if you can't afford frequent testing. If you're not on insulin or other medication, you may be able to use "block testing," in which you test blood sugar four or more times a day, one day each week (or some other pattern to get a "snapshot" of daily blood sugar), and then discuss the results with your doctor. Just be careful not to "game" the results by changing what you do on those days or times when you are testing.