The Blood Glucose Meter and Other Equipment
Your first order of business is choosing a monitor that's accurate, easy to use, and comfortable. In some cases, your insurance plan may dictate the brand or type you get. If you do have some latitude in selecting a meter, be sure to ask for recommendations. Your diabetes educator, members of your support group, your pharmacist, and your physician are all good sources.
The U.S. Food and Drug Administration (FDA) regulations for the manufacture of blood glucose monitors suggest that monitors be accurate within 20 percent of laboratory reference values. That may seem like a lot, but as long as your meter is consistent in its readings and you know how much it differs from laboratory values (which your doctor can help you determine), the variance isn't too critical. If a reading seems excessively high or low, try testing again.
Anatomy of a Meter
Blood glucose monitors come in all shapes and sizes, but there are some common features that most share:
Display. Blood glucose readings are digitally displayed on a small screen in blood plasma values of mg/dl (milligrams over deciliter.) The screen will also display error codes and instructions on calibration.
Buttons and beepers. The operator's manual for your monitor will explain the button functions. Your meter may also have special audio signals to let you know when a test is complete or alert you to highs and lows.
Test strip slot. Your blood sample goes on a test strip, which is inserted into the meter. Some meters use self-enclosed teststrip drums or cartridges, which are automatically fed into the meter and don't require any user handling.
Memory. Most modern meters have some type of memory feature that can record a predetermined number of glucose readings. Some will also let you mark readings taken around insulin doses and generate different average glucose readings.
Battery. Meters are battery powered, and many have a warning system that will tell you when the battery power starts to get low. It's a good idea to keep an extra set of batteries on hand for backup.
Other bells and whistles you may find on your glucose monitor include larger displays or voice modules for patients with vision problems, backlit displays or glow-in-the-dark cases and skins for easy night testing, and computer compatibility for downloading glucose data to special software programs or even to wireless devices. New meter technology that wirelessly transmits testing data to insulin pumps and continuous glucose monitoring systems (for calibration purposes) is also available.
Bring your blood glucose meter along to your doctor's appointments. If you're new to testing, or you're using a new brand of meter, your physician can compare the readings with laboratory values to ensure accuracy. In addition, your doctor may want to see your technique when you review your self-management.
There are a growing number of meters on the market that do more than just test blood glucose levels. Two monitors (Advocate DUO and DuoCare) combine technologies to test blood glucose and blood pressure with the same device. And the CardioChek meter performs blood glucose, cholesterol, and ketones. These multitasking meters may be a good choice if you have type 1 diabetes and want to cut down on your clutter.
Obtaining the Blood Sample
You draw the blood for testing with a lancet, which is a small, fine needle. Lancets come in a small plastic case and can be used alone or inserted into a spring-loaded lancing device, which quickly pierces the skin at a preset depth.
Lancets are available in different gauges (e.g., 21 gauge, 30 gauge) — the higher the gauge, the sharper the lancet, and the smaller the insertion hole at the test site. A higher-gauge lancet will, theoretically, make for a less painful stick (although factors such as skin sensitivity and test site factor in, too). High-gauge lancets may also be preferable for children.
Many monitors come with a separate lancing pen, while others have a lancing device integrated into the monitor itself. Lancing devices can also be purchased separately. Most spring-loaded lancing devices allow the user to set the depth of the lancet stick. Calloused skin may require a deeper stick, while a more shallow lancet stick may be better suited to sensitive skin. Because each use damages the needle slightly and makes subsequent tests more painful, it's recommended that a fresh lancet be loaded with each test. If you must reuse a lancet, clean it with alcohol first, and never use someone else's used lancet.
The lancets you use depend on three factors:
The requirements of the meter
The sensitivity and condition of your fingers (for instance, calloused fingers may require thicker lancets)
The size of the blood sample required — some meters only require a blood drop as small as a pinhead
Alternative Site Testing
To the relief of sore fingers everywhere, there is a newer breed of glucose monitors available that allow testing on less sensitive parts of the body, such as the forearm or thigh. These alternative site meters may be a good choice for you if you have sensitive fingers and you find yourself testing infrequently because of it.
However, be aware that test results from alternative sites of the body can vary from fingertip testing. Blood from the fingertips may register glucose changes in the body faster than blood from other testing sites. The FDA has required alternative site meter manufacturers to label their products with this information. If you are experiencing signs of hypoglycemia, or if you have hypoglycemic unawareness, always test from your fingertips to ensure the most accurate readings.
A test strip is a small rectangular piece of chemically treated paper that collects your blood sample for analysis by your monitor. Most meters require that you insert a new strip for each blood glucose test. However, some strips designed for specific meters come in self-contained “drums” that change the strip with each use.
Some test strips have special control codes that the meter must be calibrated against. Depending on the type of blood glucose meter you own, you may have to code your meter each time you open a new package of test strips. This process is typically fairly quick and simple.
Extreme temperature swings can affect the accuracy of meters and test strips. For this reason, avoid stowing your meter and supplies in your car in hot or cold weather, and don't leave your equipment outside in direct sunlight or extreme cold.
The accuracy of your blood tests depends on the quality and treatment of your test strips, so don't gamble with your health by cutting corners. Using expired strips is dangerous, because they may not be able to detect your glucose levels accurately. Test strips are costly, and buying strips in large quantities is usually cheaper than the smaller-quantity packages. However, if you end up with half-used containers of strips and have to throw them away, you haven't saved anything.
Many third-party manufacturers (companies that manufacture strips compatible with other manufacturers' brands of meters) produce strips for use in a variety of meter makes and models. These third-party strips can often be less expensive than the brand name. However, you need to be sure that they have been tested for use with your specific monitor. The test strip package labeling and directions for use should list this information. If you don't see your monitor make and model listed, don't buy the strips. Your monitor manufacturer often can provide you with a list of compatible third-party test strips.
Always keep your test strips out of excessive heat and moisture. The bathroom is a poor choice for storage, as humidity can affect strip accuracy. Storing your strips inside of your meter case in their original package will ensure that they stay clean.
Stuffing your meter in a back pocket or letting it float around in the bottom of your purse with ATM receipts, broken breath mints, and other assorted junk isn't a good idea. You trust your health to this piece of equipment, so treat it carefully. Many meters come with a carrying case for protection — use it. If yours didn't include a case, a well-padded cosmetic bag, shaving kit, or similar container will do the trick, too. There are also plenty of stylish meter cases available for sale in a variety of shapes and sizes.
Your test strips and control solution also need to be kept clean, dry, and at room temperature. Keep them in the case with your monitor and lancing supplies, and you'll have everything properly stored and together when you need it.