Patient and Physician Analytic Goals for Self-Monitoring Blood Glucose Instruments

The study's objective was to determine the maximum analytical error that is allowable in portable whole blood glucose meters. Interviews were conducted to derive personal reference values and significant deviations from these values for the limit of hypoglycemia, the limit of hyperglycemia, and the upper and lower limits of acceptable blood glucose for physicians and patients with diabetes at the Park Nicollet Medical Center, Minneapolis, Minnesota. Fifty patients with diabetes (30 type I and 20 type II), and 43 physicians (14 endocrinologists, 14 family practitioners, and 15 general internists) were enrolled in the study. The results showed no significant differences between type I and type II diabetic patient responses. Nor were there significant differences among family practitioner, internist, and endocrinologist responses for any of the parameters (the limit of hypoglycemia, the limit of hyperglycemia, the upper and lower limits of acceptable blood glucose for the patient, and the corresponding allowable coefficients of variation at each of these glucose levels). There were significant differences when patients were compared to physicians. Physicians require the highest degree of precision at the limit of hyperglycemia (8.4 +/- 0.28 mmol/L 150.8 +/- 5.1 mg/dL) with a maximum allowable coefficient of variation (CV) of 7%, a CV significantly lower than that of the patients (CV = 10%). Patients require the highest precision for glucose concentration around the lower acceptable limit (4.7 +/- .013 mmol/L 84.1 +/- 2.5 mg/dL), with an allowable CV of 8%, a CV significantly lower than that of the physicians (CV = 14%). The authors conclude that the accuracy required by patients and physicians at normal and higher glucose concentrations is achievable by currently available meters. Manufacturers should ascertain that glucose measurements are optimally accurate at glucose levels of 4.7 mmol/L (84.1 mg/dL) and have CVs no higher than 7%.