Diabetes Care, Vol 22, Issue 1 137-140, Copyright © 1999 by American Diabetes Association
Accuracy of pen injectors versus insulin syringes in children with type 1 diabetes
AN Lteif and WF Schwenk
Department of Pediatric Endocrinology, Mayo Clinic, Rochester, Minnesota 55905, USA.
OBJECTIVE: To compare the accuracy and precision of insulin syringes and
pen devices used by children with type 1 diabetes and their parents.
RESEARCH DESIGN AND METHODS: There were 48 subjects (32 patients, a parent
of an additional 16 patients) instructed to measure out morning insulin
doses three times from vials and/or cartridges containing saline mixed with
small amounts of [14C]glucose (solution used as regular insulin) and
[3H]glucose (solution used as NPH insulin) and to dispense the contents
into a scintillation vial. Statistical analysis was used to determine the
accuracy and precision of both methods of insulin delivery. RESULTS: The
absolute error in measuring out doses of regular insulin < 5 U was
greater with insulin syringes compared with pen injection devices (9.9 +/-
2.4 vs. 4.9 +/- 1.6%, respectively). Both were comparable for regular
insulin doses > 5 U (3.2 +/- 0.6 vs. 2.2 +/- 0.4% for syringes and pens,
respectively). The accuracy in drawing up NPH doses was similar for low and
high insulin doses (mean percent error of 7.5 +/- 1.5 vs. 5.6 +/- 1.1%).
CONCLUSIONS: Pen devices are more accurate than insulin syringes in
measuring out insulin at low insulin doses. The accuracy of insulin
syringes improves when higher doses of regular insulin are measured out and
becomes comparable to pen devices.