Patient-derived quality specifications for instruments used in self-monitoring of blood glucose

Background: Instruments for self-monitoring of glucose (SMBG) are increasin gly used by diabetic patients. Information is limited on how patients use a nd interpret SMBG results, and no quality specifications for such instrumen ts are based on the opinions of patients. Methods: Type I diabetic patients (n = 201) filled in a questionnaire elici ting daily limits for blood glucose (BG) and changes of BG considered signi ficant at different glucose concentrations. From these responses, patient-d erived quality specifications were calculated in different clinical situati ons with low, intermediate, and high BG concentrations. Results: Mean age of the patients was 31.8 years, mean diabetes duration wa s 14.7 years, and mean SMBG duration was 10.0 years with a mean frequency o f 11.2 measurements/week. The threshold for hypoglycemic symptoms was 3.0 m mol/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 pati ents ranged from 1.1 mmol/L (20 mg/dL) to 3.6 mmol/L (65 mg/dL). The analyt ical quality specifications for imprecision depended on the clinical situat ion. Excluding the hypoglycemic situation, the analytical CV needed to fulf ill the expectations of 75% of the patients was 6.4-9.7%. The analytical qu ality specification for CV at hypoglycemic concentrations was 3.1%. Conclusions: Instruments for self-measurements of glucose with an imprecisi on (CV) of less than or equal to5% and bias less than or equal to5% meet th e expectations of >75% of patients in clinical situations other than hypogl ycemia. (C) 2001 American Association for Clinical Chemistry.