The purpose of this study is to demonstrate the performance of the Guardian™ Sensor (3) with an advanced algorithm in subjects age 2 - 80 years, for the span of 170 hours (7 days).

The study is a multi-center, prospective, single-sample correlational design without controls. The purpose of this study is to demonstrate the performance of the Guardian™ Sensor (3) with an advanced algorithm in subjects age 2 - 80 years, for the span of 170 hours (7 days).

Inclusion Criteria:

1. Individual is 2 - 80 years of age at time of enrollment
2. A clinical diagnosis of type 1 or 2 diabetes for a minimum of 6 months duration as determined via medical record or source documentation by an individual qualified to make a medical diagnosis
3. Adequate venous access as assessed by investigator or appropriate staff
4. Subjects participating in the high and low glucose challenges must have an insulin carbohydrate ratio(s) and insulin sensitivity ratio. Subjects without ratios may participate under observation only

Exclusion Criteria:

1. Subject will not tolerate tape adhesive in the area of Guardian™ Sensor (3) placement as assessed by a qualified individual.
2. Subject has any unresolved adverse skin condition in the area of sensor or device placement (e.g., psoriasis, rash, Staphylococcus infection)
3. Subject is actively participating in an investigational study (drug or device) wherein they have received treatment from an investigational study (drug or device) in the last 2 weeks
4. Subject is female and has a positive pregnancy screening test
5. Female of child bearing age and who is sexually active should be excluded if she is not using a form of contraception deemed reliable by investigator
6. Subject is female and plans to become pregnant during the course of the study
7. Subject has had a hypoglycemic seizure within the past 6 months prior to enrollment
8. Subject has had hypoglycemia resulting in loss of consciousness within the past 6 months prior to enrollment.
9. Subject has had an episode of diabetic ketoacidosis (DKA) within the past 6 months prior to enrollment.
10. Subject has a history of a seizure disorder
11. Subject has central nervous system or cardiac disorder resulting in syncope
12. Subject has a history of myocardial infarction, unstable angina, coronary artery bypass surgery, coronary artery stenting, transient ischemic attack (TIA), cerebrovascular accident (CVA), angina, congestive heart failure, ventricular rhythm disturbances or thromboembolic disease
13. Subject has a hematocrit (Hct) lower than the normal reference range (please note that patients may use prior blood draw from routine care as long as done within 6 months of screening and report of lab placed with subject source documents)
14. Subject has a history of adrenal insufficiency
15. Subject is a member of the research staff involved with the study.