Patient-derived quality specifications for instruments used in self-monitoring of blood glucose.
BACKGROUND
Instruments for self-monitoring of glucose (SMBG) are increasingly used by diabetic patients. Information is limited on how patients use and interpret SMBG results, and no quality specifications for such instruments are based on the opinions of patients.


METHODS
Type 1 diabetic patients (n = 201) filled in a questionnaire eliciting daily limits for blood glucose (BG) and changes of BG considered significant at different glucose concentrations. From these responses, patient-derived quality specifications were calculated in different clinical situations with low, intermediate, and high BG concentrations.


RESULTS
Mean age of the patients was 31.8 years, mean diabetes duration was 14.7 years, and mean SMBG duration was 10.0 years with a mean frequency of 11.2 measurements/week. The threshold for hypoglycemic symptoms was 3.0 mmol/L (54 mg/dL), and the mean daily BG target window was 4.3-10.4 mmol/L (77-187 mg/dL). The mean absolute BG changes producing actions from the patients ranged from 1.1 mmol/L (20 mg/dL) to 3.6 mmol/L (65 mg/dL). The analytical quality specifications for imprecision depended on the clinical situation. Excluding the hypoglycemic situation, the analytical CV needed to fulfill the expectations of 75% of the patients was 6.4-9.7%. The analytical quality specification for CV at hypoglycemic concentrations was 3.1%.


CONCLUSIONS
Instruments for self-measurements of glucose with an imprecision (CV) of < or = 5% and bias < or = 5% meet the expectations of >75% of patients in clinical situations other than hypoglycemia.
Skeie
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NOKLUS, Norwegian Center for External Quality Improvement of Primary Care Laboratories, Division of General Practice, Ulriksdal 8c, University of Bergen, N-5009 Bergen, Norway. svskeie@online.no
Thue
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Sandberg
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D000293:Adolescent; D000328:Adult; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation* / Q000592:standards; D019411:Clinical Laboratory Techniques / Q000295:instrumentation* / Q000592:standards; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D011795:Surveys and Questionnaires