February 26, 2002
Blood Tests and Insulin Injections
Question from Hopewell Junction, New York, USA:
My nine year old son just began using an insulin pump, and his educator told us to use his fingertips rather than his forearm to get more accurate blood sugar readings. We checked the difference, and his forearm was 100 mg/dl [5.6 mmol/L] when his fingertip was 133 mg/dl [7.4 mmol/L]. Which reading is the accurate one? Is it true that you should use your fingertips rather than your forearm to get a more accurate reading? We really like using this type of monitor on his forearms and his fingertips do get a rest.
Answer:
Probably the best thing for you and your son to do is to read Is There a Difference Between Blood Glucose Measurements on the Forearm and the Fingers? on the FreeStyle web site. Very briefly, the forearm sample is some ten minutes behind the finger tip, but whilst this makes an insignificant difference in the fasting state, under any condition where blood sugar levels are changing (including the stress of multiple sticks), this time difference needs to be considered. However, it can be minimised by vigorously rubbing the forearm for a moment or two before taking a sample.
DOB
