
March 23, 2001
Blood Tests and Insulin Injections
Question from Altamonte Springs, Florida, USA:
I have had type 1 diabetes for 49 years and have experienced numerous glucose monitoring methods. Is there a clinical evaluation of the accuracy of home blood glucose monitoring devices on the market today?
Answer:
By ‘clinical evaluation’ I assume that you mean some composite of accuracy and convenience of use. The latter characteristic is really too subjective to have made for reliable comparison. Assessments of accuracy are a different story and the College of American Pathologists publishes a list of about 40 glucose measuring devices three times a year. The coefficients of variation (CV) vary between about 1 and 4. For the larger figure this means that a standard of 100 mg/dl [5.6 mmol/L] will have an approximately 80% chance of coming out between 96 and 104 mg/dl [5.3 and 5.8 mmol/L] and a 95% chance of reading between 92 and 108 mg/dl [51 and 6 mmol/L].
However these figures only apply to clinical laboratories including those in doctor’s offices where a charge is being made. They do not include home blood glucose monitors. These devices are basically microvoltmeters and though there may be some differences in the technology used in the strips, the electronics of the meters themselves are essentially the same. You could get precise information on linearity and reproducibility from the manufacturer, but you have to remember that by far the main source of variation depends on the operator. Using a number of different meters, the nurses in this clinic have obtained CV’s of around 5 with no meter standing out as obviously superior, and I imagine this is the sort of reliability that you yourself would show.
DOB