Blood glucose monitoring provides immediate feedback on the effect of daily activities such as taking medication, exercise or eating on blood glucose levels. A home blood glucose meter’s results are considered accurate if they falls within ±20% of lab results. Such meters are calibrated to use whole blood to measure glucose, whereas lab equipment uses only the plasma portion. To maintain accuracy, results from a meter should be compared to those of a laboratory at least once a year. Diabetes educators should have thorough knowledge of each meter and its accuracy so that he or she can properly educate diabetic patients.