Rapid Action Insulin (RAI) absorption and action measured by time to reach maximum insulin concentration and glucose infusion rate.

The investigators hypothesize that RAI absorption and action measured by time to reach maximum insulin concentration and glucose infusion rate during the clamp study will be significantly faster when insulin bolus is delivered using the "Quick Bolus" feature as compared to the "Standard Bolus".

Outcomes were updated at time of results entry.

Inclusion Criteria:

1. Age 18 - 30 (inclusive)
2. Clinical diagnosis of T1D of at least one year's duration
3. On Continuous Subcutaneous Insulin Infusion (CSII) therapy for at least three months
4. HbA1c <10%
5. Minimum weight requirement of at least 37.9 kg
6. Ability to comprehend written and spoken English
7. Total daily requirement of insulin between 0.6 and1.2 U/kg/day
8. Not have any other medical condition or disease known to affect insulin action and glucose control aside from T1D or treated hypothyroidism

Exclusion Criteria:

1. Medication besides insulin known to alter blood glucose or insulin action
2. Female subjects of reproductive potential that are pregnant or breast feeding, or not consistently using a barrier method or abstinence as contraception.
3. Inability to comprehend written and spoken English
4. Any other condition, which in the judgment of the investigators, would interfere with the subject's ability to provide informed consent or the investigator's ability to perform the study
5. Hematocrit less than 35% or a serum potassium less than 3.4 mmol/L

Baseline demographics were collected from the 8 who completed.

Up to 5 hours post intervention for each intervention

single blinded