Inclusion Criteria:
1. Subjects must be 18 years and older at time of enrollment.
2. Subjects must have a diagnosis of type 1 or type 2 diabetes mellitus for a minimum of 6 months and require insulin therapy through an insulin pump and/or multiple daily insulin injections (at least 1 injection daily).
3. Subjects must be available to participate in all clinical sessions with the following parameters:
* Subject must be able to fast for a minimum of 6 hours prior to Visit 1 (Screening Visit).
* Subject must be willing to perform a minimum of 4 fingerstick measurements per day.
* Subject must be willing to wear 1 Sensor on each upper arm simultaneously.
* Have adequate venous access as assessed by Investigator or appropriate staff
4. Subjects must be willing to have their glucose levels manipulated into high and low glucose levels via carbohydrate consumption, meal time, activity levels and/or insulin dosing during each in-clinic visit.
5. Subjects with type 1 diabetes mellitus must be qualified by the Investigator as appropriate to perform the glucose challenge. Subjects with type 2 diabetes can be exempt from glucose challenges.
6. Subjects with type 1 diabetes mellitus must have a known treatment regimen with a target glucose concentration and a known insulin sensitivity factor
7. In the Investigator's opinion, subjects must be able to follow the instructions provided to him/her by the study site and perform all study tasks as specified by the protocol.
8. Subjects must be willing and able to provide signed written consent.
9. Subjects must be able to speak, read and write German.
Exclusion Criteria:
1. Known allergy and not able to tolerate to medical grade tape adhesive.
2. Presence and unresolved of extensive skin changes/diseases at Sensor wear site(s) that preclude wearing the Sensor(s) on skin (e.g. extensive psoriasis, recent burns or severe sunburn, extensive eczema, extensive scarring, extensive tattoos, or dermatitis herpetiformis);
3. Subjects who have or are:
* Female of child-bearing potential age:
* Has a positive pregnancy screening test no more than 72 hours prior to the Insertion Visit
* Who is sexually active should be excluded if she is not using a form of contraception deemed reliable by the Investigator
* That plans to become pregnant during the course of study.
* Diagnosed with hemophilia or any other bleeding disorders
* Acute or chronic kidney disease (Estimated eGFR less than 30 mL/min/1.73m2).
* End stage renal disease and currently managed by dialysis or anticipating initiating dialysis during the course of study.
* Any history of psychiatric conditions that, in the opinion of the Investigator, would pose a risk for participation or interfere with compliance in this study.
* Adrenal Insufficiency
* Current or know history of coronary artery or cardiovascular disease that is not stable with medical management including but not limited to being implanted with a pacemaker, advanced congestive heart failure, recent stroke, myocardial infarction, unstable angina, coronary artery bypass surgery, coronary artery stenting, transient ischemic attack (TIA), cerebrovascular accident (CVA), angina, ventricular rhythm disturbances or thromboembolic disease.
* Any condition that, in the opinion of the Investigator, would interfere with their participation in the study or pose excessive risk to study staff. Some examples of conditions that Investigators may consider exclusionary are active illegal substance use; or active psychiatric disorder. Subjects with HIV, Hepatitis B or Hepatitis C infection are excluded from the study.
* Anticoagulant treatment and platelet inhibition (with the exception of acetylsalicylic acid (ASS, daily dose rate \<300 mg), Phenprocoumon (e.g. Marcumar), NOAK (e.g. Dabigatran,Rivaroxaban)
* Chronic use of steroids in adrenal suppressive doses
* Prior to enrollment, subject has had:
* Severe hypoglycemia resulting in loss of consciousness within past 6 months. Severe hypoglycemia is defined as having low blood glucose levels that require assistance from another person to treat.
* History of Diabetic Ketoacidosis (DKA) within the past 6 months, unrelated to an intercurrent illness, infusion set failure or initial diagnosis.
* History of a seizure disorder within the last 6 months
* Hypoglycemia unawareness. It presents clinically as the patient's inability to perceive hypoglycemic symptoms.
* Severe diabetes related complications. Such conditions include, but are not limited to, severe macro angiopathy, severe micro angiopathy, severe neuro-, retino- or nephropathy.
* Required or scheduled to have a Magnetic Resonance Imagining (MRI) scan, Computed Tomography (CT) scan, or diathermy during the study wear period.
* Insulin-dependent type 2 subjects that receive sodium-glucose cotransporter 2 inhibitor (SGLT2 inhibitor) treatment\[15\]
* Hematocrit (Hct) level lower than 10% below the normal reference range (\*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)
* Weight less than 110 pounds (50 kg)
4. Participated in another clinical trial within 2 weeks prior to screening or are intending to participate in another clinical trial during the study.
5. Unable to follow clinical protocol for the duration of the study or is otherwise deemed unacceptable to participate in the study per the Investigator's clinical judgment.
6. Legal incompetence or limited legal competence
