May 14, 2007
Question from New Jersey, USA:
My daughter is using a CGMS system for three days from her endocrinologist’s office. I’ve gotten a few different answers on the margin of error for these systems, ranging from 40% to no more than 20%. We seem to be seeing wide disparities between her fingerstick numbers and her CGMS numbers. Is this normal? Is it related to her age (five)? Or, is it likely an isolated incident? My question is mostly out of curiosity, but I imagine others have similar experiences.
Original research suggested about 30% errors, mostly in the hypoglycemic range. Latest versions are in the 10 to 15% error range. These errors and “drifts” can be decreased with more calibration, i.e., three to four times a day instead of one or two times a day. You should discuss this with your pediatric diabetes team since they will know which systems you are using and give you more specific advice.