The purpose of this multi-center, prospective clinical study is to evaluate the performance of a novel, implanted Senseonics continuous glucose monitoring system (Senseonics CGM System) compared to Yellow Springs Instrument (YSI) glucose analyzer reference standard measurements using a next generation transmitter and algorithm. Other measures evaluated will be the effects of compression on performance and the safety of the Senseonics CGM system.

Inclusion Criteria:

1. Adult subjects, age ≥18 years
2. Clinically confirmed diagnosis of diabetes mellitus for ≥1 year
3. Subject has signed an informed consent form and is willing to comply with protocol requirements

Exclusion Criteria:

1. History of severe hypoglycemia in the previous 6 months. Severe hypoglycemia is defined as hypoglycemia resulting in loss of consciousness or seizure

2. History of diabetic ketoacidosis requiring emergency room visit or hospitalization in the previous 6 months

3. Female subjects of childbearing capacity (defined as not surgically sterile or not menopausal for ≥ 1 year) who are lactating or pregnant, intending to become pregnant, or not practicing birth control during the course of the study.

4. A condition preventing or complicating the placement, operation, or removal of the Sensor or wearing of transmitter, including upper extremity deformities or skin condition.

5. Symptomatic coronary artery disease; unstable angina; myocardial infarction, transient ischemic attack or stroke in the past 6 months; uncontrolled hypertension (systolic>160 mm Hg or diastolic >100 mm Hg at time of screening); current congestive heart failure; history of cardiac arrhythmia (benign Premature Atrial Contractions (PACs) and Premature Ventricular Contractions (PVCs) allowed).

   Subjects with asymptomatic coronary artery disease (e,g, coronary artery bypass graft (CABG), stent placement or angioplasty) may participate if negative stress test within 1 year prior to screening and written clearance from Cardiologist documented.

6. Hematocrit <30% or >55%

7. History of hepatitis B, hepatitis C, or HIV

8. Current treatment for a seizure disorder unless written clearance by neurologist to participate in study

9. History of adrenal insufficiency

10. Currently receiving (or likely to need during the study period):

    immunosuppressant therapy; chemotherapy; anticoagulant/antithrombotic therapy (excluding aspirin); glucocorticoids (excluding ophthalmic or nasal). This exclusion does include the use of inhaled glucocorticoids and the use of topical glucocorticoids (over sensor site only); antibiotic for chronic infection (e.g. osteomyelitis, endocarditis)

11. A condition requiring or likely to require magnetic resonance imaging (MRI)

12. Known topical or local anesthetic allergy

13. Known allergy to glucocorticoids

14. Any condition that in the investigator's opinion would make the subject unable to complete the study or would make it not in the subject's best interest to participate in the study. Conditions include but are not limited to psychiatric conditions, known current or recent alcohol abuse or drug abuse by subject history, a condition that may increase the risk of induced hypoglycemia or risk related to repeated blood testing. Investigator will supply rationale for exclusion

15. Participation in another clinical investigation (drug or device) within 2 weeks prior to screening or intent to participate during the study period

16. The presence of any other active implanted device (as defined further in protocol)

17. The presence of any other CGM sensor or transmitter located in upper arm (other location is acceptable)