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Diabetes Talks

How Do Blood Glucose Meters Work?

Time: 2022-12-20 Hits: 288

How Do Blood Glucose Meters Work?

It's time to check your blood sugar levels. Your glucose meter is on the table. You insert a new test strip, load a fresh lancet into your lancing device, snap the tiny needle into the side of your finger, and squeeze until a small amount of blood gathers into a red dome. You apply the drop of blood to the edge of the strip and watch as your glucose monitor counts down to reveal a blood glucose measurement in real-time. A number with meaning. That number can change the course of your entire day. Or, it could just be a checkpoint that passes by until the next finger-stick. 

Good job! You've done your part in self-monitoring and diabetes management. But have you ever wondered how this key diabetes technology works? 

How your glucose meter measures the sugar in your blood?

Blood glucose test strips contain a capillary that sucks the blood up into the test strip. It reaches an enzyme electrode where the blood sample is mixed with  a glucose oxidase enzyme, and an electrical current is created by the glucose meter. The charge passing through the electrode is proportional to the amount of glucose in the blood sample. So, if your test results read 90 mg/dL, there are 90 milligrams of glucose in a deciliter of your blood. 

Alternative site testing

Fingertips are sensitive because of the high concentration of nerves. To avoid the pain, many people draw blood from other areas. Most blood glucose meters were originally designed to be used with capillary blood taken from a finger prick due to the highly accurate results from these blood glucose readings. Some meters, including all of the meters we carry, have been approved for alternate site testing (AST), which is blood drawn from areas other than your fingertips, such as your palm or arm. If you are interested in AST, read your meter directions to find out if it's approved for alternate site testing before attempting to make the change.

Glucose meter accuracy

When you test your blood sugar using any glucometer the result shows you an estimate of the amount of glucose in your blood. The U.S. Food and Drug Administration (FDA) has a medical device accuracy standard for all glucose monitoring systems saying that glucose meters must show results that are within 20% of a laboratory result 99% of the time (ours is within 15%, 99% of the time). Many factors can affect the accuracy of your Blood glucose monitor's results, including temperature, levels of other substances (such as ascorbic acid) in your blood, traces of other elements on your skin (such as food residue), water, heat, the age of your test strips (check expiration dates), and many more.