Accuracy of pen injectors versus insulin syringes in children with type 1 diabetes.
OBJECTIVE
To compare the accuracy and precision of insulin syringes and pen devices used by children with type 1 diabetes and their parents.


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.
Lteif
A N
AN
Department of Pediatric Endocrinology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Schwenk
W F
WF
D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D007279:Injections, Subcutaneous / Q000295:instrumentation* / Q000379:methods; D007328:Insulin / Q000008:administration & dosage* / Q000627:therapeutic use; D015203:Reproducibility of Results; D013594:Syringes; D014316:Tritium
D001786:Blood Glucose; D002250:Carbon Radioisotopes; D007004:Hypoglycemic Agents; D007328:Insulin; D014316:Tritium; D005947:Glucose