Glucose meters have come a long way in the past 45 years. The first blood glucose meter, (commonly abbreviated as BGM), was a "primitive" device as compared with today's high-tech meters. Using the first glucose meter, "Destrotrix," involved dropping an entire drop of blood on a reactive paper, waiting one minute, rinsing with water, and comparing the color of the paper to a comparative color chart. With current technology, glucose readings have become less of a hassle and extremely convenient. With the large variety of meters on the market, choosing the meter that is right for you is important. The three important factors that you should consider in a glucose meter are accuracy, ease of use, and convenience.

How Glucose Meters Work

There are two methods used to determine the glucose level either optical or electrostatic. The optical method is done by measuring the reflective light (reflectance photometer - optical) to determine the blood glucose level. It works by taking a blood sample, applying it to a test strip, and then shining a measured amount of light on it. The amount of light that is reflected back is then measured; the amount of reflected light indicates how much glucose is present in the blood sample (higher amount of light reflected means higher amount of glucose). This technology is found in many older meters and accuracy isn't consistent. Most modern meters now incorporate electrostatic technology. This works by measuring the voltage (electrons) level using electrochemistry to determine the blood glucose level. This method is done by applying a blood sample to a test strip. Then an enzyme on the test strip called Glucose Oxidase removes one electron from the glucose which is converted into gluconolactone. The electron that is removed is read as a voltage by the meter. The number of electrons present is related to the glucose level in the blood (higher number of electrons, the higher the glucose level and the higher voltage reading on the meter).

A new type of technology based on digital signal process (DSP) has recently made its way into glucose meters. This new technology is called dynamic electrochemistry, which is an upgrade from the original electrochemistry. Static electrochemistry involves one signal that is measured by one measurement. Dynamic electrochemistry uses various sophisticated algorithms to compute many measurements based off a signal. Dynamic electrochemistry allows for more accuracy, consistency, and accounts for variations in temperature and elevation issues. Because static electrochemistry is based on only one measurement, factors such as dirty fingers, double-dosing, not enough blood, and chemical interference may have a serious impact on a meters' accuracy. With dynamic electrochemistry, the impact of these common factors is reduced significantly. This technology was developed by Agamatrix and is found exclusively in their WaveSense products.

Comparing Meters

Choosing the correct BGM for you is important in maintaining your health. A good glucose meter should be very accurate. Accuracy is important because it measures exactly how much glucose is actually present in your blood. Out of all the meters in the market, I have found that the top three meters in terms of accuracy are the WaveSense Keynote, the Abbott Freesstyle Flash, and Ascencia by Bayer Contour. In a comprehensive study in November 2006, YSI probes were used to find the exact level of glucose in blood samples. Using that value as an exact measurement, home glucose meters were put to the test. Comparing the major meters in the market, the WaveSense Keynote was 95.0%, the Abbott Freestyle Flash was 95.2%, and Ascencia by Bayer Countour was 84.0% of the time within an acceptable accuracy range. These are the top three meters in the market in terms of accuracy.

Another criterion that is important is consistency. Consistency is important for all BGMs because it tells you how repeatable the meter is. In other words, accuracy is important only if it can be accurate every single time. Therefore, consistency is also an important part of choosing a meter. In regards to consistency, The WaveSense Keynote, Abbott Freestyle Flash, and Ascencia by Bayer Countour once again are the leaders in consistency. Consistency was measured by taking a high number of samples with the same level of glucose. Then, the variation was computed by averaging the amount of difference each sample had with each other. In other words, the lower amount of variation, the more consistent the meter is. The WaveSense Keynote had a variation of 2.7% with low glucose levels and 2.8% with high glucose levels. The Abbott Freestyle had a worse consistency level because its consistency would go as high as 2% to 7%. But most of the meters had a variation less than 5%. Also, Ascencia also had a variation less than 5% during optimal conditions and a variation of about 5% with diabetics.

The final area of consideration when choosing the right glucose meter is the ease of use. Ease of use is important because you will be using your meter constantly and your meter should be solving your problems, not creating new ones. In this category, I have found that the WaveSense Keynote, Abbott Freestyle, and the Roche Accu-Check are the most convenient and user-friendly meters in the market. All three meters are very compact so that they can fit in the palm of your hand. Each meter also has large and clear numbers to allow easy reading. However, only the WaveSense Keynote and the Abbott Freestyle have a convenient backlight for reading in dim light. Each meter has a sufficient amount of memory to allow navigation through past readings. Only the WaveSense Keynote has a USB port that allows simple connection to a PC to permanently store past information. Sample size is extremely small in all three of these meters, resulting in less pain for the user. Sample time is also a factor; the WaveSense is usually a 1-2 second testing time, although it can be as high as 12 seconds depending on the sample size. The Abbott Freestyle has a 7 second average test time. The Roche Accu-Check has somewhat of a longer testing time at 26 seconds.

Accuracy and consistency are very similar with the WaveSense Keynote, Abbott Freestyle, and the Ascencia. However, I have found that the best meters are the ones that cater to the users themselves. The ease of use is what distinguishes excellent meters from average meters.

The WaveSense Keynote has a number features that no other meter in the market has yet to integrate. One such feature includes a hypo/hyperglycemic alert. It can be easy to misread a number, even for the most experienced diabetics. In the United States, glucose levels are reported in the units of Mg/dl (milligrams per deciliter) while in Europe and Canada, glucose levels are reported in mmol/l (millimoles per liter). There is about an 18 times difference in glucose levels in these different units. A simple hypo/hyperglycemic alert can act as a double-check to make sure you make the correct decision since there have been reported mistakes because of using a non-American meter.

Another unique feature that WaveSense Keynote has is the hematocrit auto correction ability. Hematocrit is the measure of red blood cells per volume of blood. Within everybody's blood, there are not necessarily equal amounts of red blood cells per sample. Using dynamic electrochemistry, a biosensor that no other meter currently has, the WaveSense is able to distinguish when there is a lower or higher hematocrit count in the sample. The hematocrit auto correction feature can identify this problem and adjust its reading to accommodate varying hematocrit. In other words, dynamic electrochemistry reduces the amount of errors your meter takes to accurately measure your blood glucose. It also has a feature that compensates for meal-time averages. Since each body is uniquely different, the glucose increase also may vary from each person. The WaveSense meal-time average displays your average scores before mealtimes. This allows users to think about their daily diet and its direct effect on their blood glucose. I believe this to be essential for all diabetics because it is able to cater to virtually everybody in a personal way. Another unique feature is the double redundant power supply. A double redundant power supply is perhaps the most convenient and life-saving feature. Losing power to your meter can happen virtually anywhere. Having a backup supply gives you that extra time you need to get your reading when all other meters in the market would fail.