Blood glucose meters
Self-monitoring of blood glucose is the most important tool available to a patient for determining their glycemic control. This test is simple to perform. It involves taking a small lancet to poke a finger. Usually, this testing is performed just off to the side of the finger's tip, although some meters do allow testing at other sites, such as the forearm. Then, a small quantity of blood is placed on a testing strip that has been inserted into a meter that reports the glucose value.
The meter determines the blood glucose level by measuring the chemical reaction on the reagent strip. Results obtained using a glucose meter are more accurate than those obtained without the meter (that is, with reagent strips alone). However, the results using a home meter vary as much as 20% from the more accurate measurements in a hospital or clinical laboratory. Fortunately, portable meters are accurate enough for home monitoring and self-adjustment of insulin doses at home.
It is important to know that reagent strips are calibrated for specific meters. Many meters need to be calibrated each time a new box of test strips is used. Inappropriate calibration will lead to errors in glucose readings. Using incompatible strips and meters will give unreliable glucose readings.
Errors can also be caused when:
meters are improperly calibrated;
the meter is dirty;
the battery in the meter is dead;
reagent strips are stored improperly;
the reagent strips have expired;
not enough blood is applied to the reagent strip;
blood is not left on the reagent strip long enough, or is left too long, before reading;
the test is performed under the wrong conditions of temperature and humidity; or
patients are dehydrated.
The main advantage of self-monitoring blood glucose is its immediate feedback. The immediacy of the result allows the individual to make decisions in terms of insulin, diet, and exercise that immediately improve glucose control. This, in turn, gives people more control over their diabetes and allows them to adapt their diabetes treatment plan to their lifestyle. Providing regular results to a health care professional allows for more frequent and therapeutic adjustments of medications. This improves symptoms and diabetic control, especially in the outpatient setting.
The main disadvantages of the self-monitoring of blood glucose are cost, discomfort, and inconvenience (such as interrupting one's usual activities to do it). In addition, some patients experience a feeling of frustration at seeing high blood glucose results when they expected lower readings.
One could say, "The thing about blood testing is that I know what my sugar is, and the bad thing about glucose testing is that I know what my sugar is."
The information obtained from self-monitoring blood glucose is valuable to all people with diabetes, even those controlled with diet and exercise, and those who require oral medication. Many physicians routinely give all their patients with diabetes a glucose meter, along with an individualized testing schedule. This
schedule ranges from once daily up to six times each day, depending on patient needs. Introducing the self-monitoring of blood glucose
is effective, in conjunction with diet education.
Many meters are available on the market and differ in attributes. They vary in the amount of blood used, speed to display results, font size of the display, ability to store readings in memory, and capability to download data. Some meters no longer require calibration. Newer meters function as a portable digital assistant (PDA) for health, allowing patients to enter other laboratory values, dates, and results of health visits. Newer meters may also store the strips right in the meter, thereby allowing the patient to avoid handling the strips. They may also allow for a patient to flag readings
taken after eating vs. before a meal. Examples of glucose meters available over-the-counter are Accu-Chek III®, Glucometer Elite XL®®, and One Touch Ultra.
Software programs and mobile applications are also available that can help people with diabetes manage their glycemic control. Depending upon the program, users can store and chart glucose levels, lab values, doctor visits, or other health parameters.