How to select a blood glucose meter

by Myriam Z. Allende-Vigo, MD, MBA, FACP, FACE

Congratulations! You have decided to monitor your blood glucose (“sugar”) and so take control of your diabetes. You have heard about the benefits of controlling your blood sugar levels. You know that you are going to feel better and delay or even stop complications that may arise from having high blood sugar. Now you need supplies to monitor your blood sugar levels. Where do you start? How do you select a blood sugar meter?

This is not a one-size-fits-all issue. Blood sugar meters each have different features. But they all have something very important and crucial in common; they measure the blood sugar fairly accurately, especially between 100-240 mg/dL. The measurement that you get by any meter needs to be consistent with actual blood sugars, otherwise the Food and Drug Administration (FDA) will not approve the meter. Blood sugar meters are capable of measuring the blood sugar by a reaction between blood and chemicals in the testing strip. Because the chemicals can vary between meter types, specific blood sugar monitors will be required if you have certain conditions, such as being on dialysis through a catheter in your abdomen. This should always be discussed with your diabetes specialist.

Some blood sugar meters require calibration to check that the meter is reading correctly. If the reading of a drop of a “control” solution gives a value within the manufacturers’ expected values, the meter is working well. Certain meters will also need coding calibration, while others do this coding calibration automatically. If the meter requires coding calibration with test strips, the test strip container will come with a number on the strip box or a chip that will show a number, and a code. It is critical that the code on the strips or chip and the code that appears on the screen of the meter must match. If the codes don’t match, the blood sugar reading is not accurate.

Some meters use blood from the fingertips (you have to prick your fingertip to obtain a drop of blood). Other meters allow you to use other sites to obtain the drop of blood, such as the forearms, earlobe, thigh, or palms. Various meters have large screens with big numbers. Some meters have small screens with small numbers. Most meters have a memory feature that can record in the machine’s memory the blood sugar value and date and time the test was done. The meter’s memory may hold from a few dozen measurements to several hundred values. A number of meters are downloadable into a computer spreadsheet. Make sure that the date and time on your meter really is accurate before you first use it to test your blood sugar levels. After that, a good time to check the accuracy of your meter’s entered date and time is each time you change the battery.

Most meters can give you a reading within a few seconds; some meters are faster than others. Some meters can talk to you and tell you the blood sugar level, and date of the reading, which can be especially useful if your vision is limited. Certain meters speak and can even give directions in several languages, such as English or Spanish, on the visible screen. Please check that the designation of meter’s units of blood sugar matches the units used in your country. In the United States, “mg/dL” is used, in other countries “millimoles” are used. These are very different number designations!

The meter is a machine, so it could malfunction. The control solution should be used to check the validity of your meter at least once a month.

It is also important to collect the correct amount of blood; some strips make this easier by just absorbing the amount needed. Humidity may affect the strips and the reading. Even altitude can interfere with fingerstick accuracy. Meters differ on what they can read; some start as low as 40 and read up to 600. Hi or Low readings can mean different things on different machines. Some meters turn on or off automatically. Instructions, for how to use the meter, may come printed or on videos. The instruction manual will state the properties and capabilities of the meter at different temperatures and different altitudes. Most meters offer toll-free telephone numbers with around-the-clock support. The instruction manual will state the properties and capabilities of the meter at different temperatures, and different altitudes.

Do not expect to find exactly the same number if you test on different parts of your body, use different strips, or get results from or in the laboratory. What you can expect is to have a fairly good idea of the levels of blood sugar in your blood at the time tested if the procedure was properly done. Blood sugar levels checked by fingerstick will be more accurate if your blood sugars are suddenly dropping or rising. These would not be times to check at sites other than the fingertips.

So, how do you choose a blood sugar meter among the hundreds available? You have to do your homework, then check with your diabetes specialist to review your final choice to choose the best one for your needs.

Dr. Allende-Vigo is a Puerto Rican physician who has dedicated her professional life to taking care of patients with endocrinologic disorders. She has lectured and researched in the fields of diabetes mellitus, lipid disorders and osteoporosis. Dr. Allende-Vigo has been involved in academics as Professor of Medicine at the University of Puerto Rico (UPR), contributing to the formation of medical students and residents in Internal Medicine, Family Medicine and Endocrinology. She has been very active as member of the AACE Board of Directors and Chair of the International Membership Committee of AACE. Dr. Allende-Vigo is also past president of the Puerto Rican Society of Endocrinology and Diabetology (SPED).