- Laboratory glucose values report plasma glucose levels. Most
newer glucose meters also give the level of plasma glucose. Older
meters (such as the one touch basic) measure and report whole blood
glucose levels. Recall that whole blood glucose levels are about 12%
lower than plasma glucose levels.
- Glucose meter results have about a 10% variation. Thus you and
your patients may be frustrated when comparing results from one meter to
the next (especially if one meter is measuring whole blood, and the other
- When alternative site (forearm) meters are used, there may be false
results during times of rapid glucose flux. Specifically, the values
may be suspect during hypoglycemic episodes and postprandially.
Thus, the fingertip should be used during those times.
- Finally, false low finger tip glucose levels have been reported
in vasoconstricted patients (Rushakoff
RJ, Lewis SB: Case of Pseudohypoglycemia. Diabetes Care 2001 24:
and hypotensive volume depleted patients (Atkin
SH, Dasmahapatra A, Jaker MA, Chorost MI, Reddy S: Fingersick glucose
determination in shock. Ann Intern Med 114:1020–1024, 1991)