If you think you’ve done everything right but still don’t trust your results, do a test using the control solution that is made for your meter. Control solution is a glucose solution that is designed to give a reading in a predetermined range when applied to a blood glucose test strip. The predetermined range will be marked on the vial of test strips or possibly on the bottle of control solution itself. If your reading is within the range indicated, your meter and strips are working properly. If not, make sure your control solution isn’t expired, and repeat the test. If your results are still outside the control solution range, call your meter’s customer service number for help.
Another tool to see how well your diabetes plan is working is the A1C test, also called the glycosylated hemoglobin, or HbA1c, test. This blood test gives an indication of overall blood glucose control over the previous 2–3 months by measuring the percentage of one type of hemoglobin molecules (found in red blood cells) that are attached to glucose molecules, or are glycosylated. This percentage gives a very good estimate of your average blood glucose level over that time. Currently, the ADA recommends a target A1C of less than 7% (equivalent to an estimated blood glucose average of 154 mg/dl), while the American College of Endocrinology (ACE) recommends a target A1C of 6.5% (equivalent to an estimated blood glucose average of 140 mg/dl) or lower. In research studies, higher A1C levels have been associated with a higher risk of diabetes complications.
The ADA’s recommended frequency for measuring A1C is two to four times a year. In the near future, your health-care provider may tell you your results both as a percentage and as an estimated average glucose level to make it easier to compare to your home blood glucose monitoring results. (To see how A1C percentages compare to the results you get on your meter, see “Average Blood Glucose.”)
An A1C test result that is higher than expected usually indicates that there are times when you are not monitoring that your blood glucose level is high. Varying the times of day you monitor can help to uncover when these times are and assist your health-care provider in making appropriate treatment recommendations.
When things go wrong In spite of your best efforts, it’s likely there will be times when your blood glucose level is higher or lower than your target range. Knowing how to respond is an important part of your diabetes care plan.
Hyperglycemia. When your blood glucose gets too high, it is called hyperglycemia. Warning signs may include feeling very thirsty, having to urinate often, feeling very tired or weak, or having blurred vision. In many cases, however, hyperglycemia causes no symptoms at all.
Hyperglycemia can be caused by not taking your medicine as prescribed, which can happen for any number of reasons, including forgetting to take it, choosing not to take it, running out of medicine, or having a problem with your method of medicine delivery, such as a malfunctioning insulin pump. Some diabetes medicines, including insulin, can also lose effectiveness if they are old or have been stored improperly. Hyperglycemia can also be caused by an illness or infection, by certain medicines used to treat conditions other than diabetes, by eating too much, or by being less active than usual.
How you respond to high blood glucose depends in large part on how high it is and what the likely cause is. If you’ve just eaten a meal and your blood glucose level is somewhat higher than you’d like, taking a walk and drinking some water can help to bring it down, and reassessing your portion sizes, food choices, and carbohydrate intake at that meal may help to prevent high blood glucose in the future. If high blood glucose does not appear to be related to a recent meal, think through the other possible causes, such as forgetting to take a dose of medicine or coming down with a cold, to determine what might be going on.