A glucose meter (glucometer) tests your blood sugar level. You use the meter after you prick your finger and release a drop of blood onto a test strip. Today's glucometers use an enzyme to read the glucose level. Usually this is glucose oxidase or hexokinase. The enzyme reacts with the glucose in the drop of blood. The reaction may produce a color change. The meter translates this into a number. This is the blood glucose level. It is measured in milligrams per deciliter (mg/dl).

Alternatively, some meters measure electric current generated by the enzyme in response to the glucose. Then they translate this into a number reading.

Different meters provide different information. If the meter has a memory, it will keep track of blood glucose levels. If your meter doesn't have a memory (and sometimes even if it does), you will want to keep track of your numbers yourself. Record your glucose levels. Then you can make a simple graph to show patterns. Your meter also may tell you what percent of your readings are in target range and how often they are high or low.

Most newer meters include computer software. This allows you to download the results to a computer. Then you or your doctor can chart or graph the results and print them out.