Blood glucose readings are key to assessing your overall diabetes plan. Recording your blood glucose monitoring results in a format that allows you to see patterns is important. If you monitor once daily, you can do your checks at different times of day on different days to get a more complete picture of how your blood glucose level typically runs over the course of a day. Meters with memory function can be useful; however, it can be difficult for you or your health-care provider to visualize a pattern just by scrolling back in the memory. Recording values on a designated record sheet can help both you and your diabetes care team to best evaluate patterns.
Some people may prefer to link their meter with a computer software program and print out the records. You can find out if a software program is available for your meter, as well as more about it, by either calling the meter company’s toll-free number or by accessing the company Web site, which may be printed on the back of the meter and/or in the meter packaging.
Troubleshooting your meter
If you use your meter often, you will get to know it well. If at any time you feel it is not working, the settings (such as date and time) are incorrect, or the blood glucose numbers you are getting are not what you expect, check it out.
If you are feeling symptoms and the number on your meter doesn’t match, recheck your blood glucose level. Sometimes improper technique or too much or not enough blood on the test strip can lead to inaccurate readings. Double-check your test strips, too. Test strips that have expired or have been exposed to extreme heat or cold often produce inaccurate results.
You should also check to make sure that your meter has been properly calibrated, or that the code number entered into the meter matches the code found on the test strip package. While some newer meters have automatic coding features, others require you to enter a code or insert a special chip or strip every time a new package of test strips is started. Each time you monitor, make sure that the number displayed on the meter matches the code number printed on the package of strips.
If your technique, test strips, and calibration are all OK, try using control solution. Blood glucose meters typically come with a bottle of glucose control solution that can be used to verify that the meter and testing supplies are in working order. To perform a test, apply a drop of solution to a test strip, following any specific instructions that accompany the solution bottle. The control solution is then read by the meter just like a blood glucose sample. The solution contains a “controlled” amount of glucose that, when applied correctly, should read within a certain designated range that is usually printed on the test strip packaging. Before using control solution, check to make sure that it has not passed its expiration date (printed on the bottle) or its discard date (usually the date opened plus three months), which you should mark on the bottle the first time it is opened. If the result of your control solution test does not read within the specified range, you may want to repeat it to verify. If it is still not within the recommended range, then calling the meter company is the next step.
Each meter has a customer service telephone number, which is usually toll-free (or free of charge). This number is most commonly found on the back of the meter and/or in the literature provided in the packaging. Trained personnel are on the phone line to assist with troubleshooting the meter and obtaining a new meter if, in their opinion, your meter does not seem to be in working order.
When you have blood drawn in a laboratory, you may want to check your blood glucose with your meter at the same time and compare the lab’s plasma glucose levels with your meter’s result. (In fact, some labs routinely do this for you when taking blood for an HbA1c test.) Your blood glucose meter is considered accurate if its results fall within 20% of the laboratory results. Also, when comparing results, it is important for you to know whether your meter provides whole-blood or plasma-calibrated results. While older meters provide whole-blood readings, most new meters recalculate their results to indicate only the amount of glucose present in the plasma, or fluid part of the blood. Because glucose is concentrated in the plasma, plasma-calibrated values are generally about 12% higher than whole-blood values. Laboratory tests measure your plasma glucose level, so it is important to make the mathematical adjustment when comparing lab test results to results obtained on a whole-blood meter. If you’re not sure how to do this, ask your doctor or diabetes educator for help.