Standardized Evaluation of Nine Instruments for Self-Monitoring of Blood Glucose

BACKGROUND: Instruments for self-monitoring of blood glucose (SMBG) should undergo a standardized evaluation including a user-test before being marketed. In this study the results from standardized evaluations of nine different SMBG instruments are presented, and the standardized evaluation is discussed. METHODS: Approximately 80 diabetes patients using three lots of test strips participated in each evaluation. Half of the patients were educated in how to use the meter, and the evaluations were carried out by both medical laboratory technologists (MLTs) and patients. Questionnaires were used to assess the user manual and the user-friendliness of the instrument. RESULTS: The imprecision obtained by the patients (coefficients of variation CVs of 3.2-8.1%) were generally higher compared to that by the MLT (CVs of 2.3-5.9%). Three of the nine instruments did not achieve the quality goal based on the recommendation in the International Organization for Standardization's ISO 15197 guideline in the hands of diabetes patients. The bias from the comparison method ranged from -10.4% to +3.2%. There were significant lot-to-lot variations and hematocrit effects for some of the instruments. Temperature difference between the instruments and the test strip caused deterioration of the quality in one instrument. The user-friendliness was in general acceptable. CONCLUSIONS: The quality of instruments for SMBG seems to have improved during recent years, although there are still analytical problems. A standardized evaluation protocol is necessary and should be regularly revised taking into account the development of new technology and the needs of the patients.