The aim of the study is to demonstrate the safety and performance of a novel non-invasive glucose monitoring device, to collect data and reference measurements for establishment of calibration models and to evaluate the instructions for use for the device. This study will be an explorative study with 10 study subjects.

The Investigational Medical Device (IMD) for this investigation is the Prototype 0.5 (P0.5) developed and manufactured by RSP Systems (RSP). The device is intended for non-invasive interstitial intermittent glucose monitoring in persons (age 18 and older) with diabetes. The technology relies on the well-established capacities of Raman spectroscopy for directly detecting glucose subcutaneously. The Raman spectroscopy physical principle relies on the fact that when laser light of a given wavelength interferes with a molecule, a small fraction of the incident light will interact with the vibrational states of the molecule, causing the photons to lose a portion of their energy which will change the wavelength of the light. The scattered light will be collected by the optical probe head and analyzed with advanced algorithms to correlate the signal to glucose concentrations. Data collected from the IMD will be paired with validated glucose reference values collected by the finger sticking method.

Inclusion Criteria:

• Male and female subjects ≥18 years of age
• Individuals diagnosed with type 1 diabetes. Gestational diabetes excluded
• Skin phototype 1-4
• Willing to perform up to 12 finger sticks during each day of out-patient measurements and up to 40 finger sticks at the two in-clinic study days
• Wireless internet connection at home to be used in the study

Exclusion Criteria:

• For female subjects: Pregnancy or subject is attempting to conceive or not willing and able to practice NCA approved birth control during the study duration
• For female subjects: breastfeeding
• Subjects currently participating in another study
• Subjects not able to understand and read German
• In investigator's opinion, subject is not able to follow instructions provided and as specified in the protocol
• Subject not able to hold hand/arm steady (including tremors and Parkinson's Disease)
• Extensive skin changes, tattoos or diseases on right hand thenar (sensor application site)
• Known allergy to medical grade alcohol
• Hemodialysis
• Systemic or topical administration of glucocorticoids at the right hand for the past 7 days or during the study period expected
• Medical history or any condition that may, in the opinion of the investigator compromise the subject's ability to participate
• Comorbidity or concomitant medical condition which, in the opinion of the Investigator, could interfere with the study or present a risk to the safety or welfare of the subject or study staff
• Severe diabetes related complications such as advanced autonomic neuropathy, kidney disease, foot ulcers, legal blindness, or symptomatic cardiovascular disease as evidenced by a history of cardiovascular episode(s)
• Dependency from the sponsor or the clinical investigator (e.g. co-workers of the sponsor, the study site, and/ or their families)
• Severe hypoglycemia resulting in seizure or loss of consciousness in the 3 months prior to enrollment
• Hypoglycemia unawareness
• Subjects who have participated in the study IDT-1639-RO

One group will receive the instructions for use and the other will not.