In the past twenty years there have been significant improvements in the accuracy of handheld glucose meters. Patient use has resulted in substantial improvements in diabetic control and insulin therapy. Capillary whole blood is easily obtained and glucose concentration is derived on simple to use, portable meters. Since whole blood glucose is lower than plasma glucose, the meters are programmed to correct the value before presenting the result; therefore, the whole blood glucose meter result correlates to serum or plasma results.
The Clinical and Laboratory Standards Institute (CLSI) has set standards for correlation between glucose meter and laboratory measured glucose levels. If the laboratory measured glucose is >75 mg/dL, the glucose meter result should be within 20%. For laboratory measured values <75 mg/dL, the glucose meter result should be within 15 mg/dL.