This explorative clinical investigation has been launched to collect spectral Raman data paired with validated glucose reference values in persons with diabetes.

Inclusion Criteria:

• Male and female subjects minimum 18 years of age
• Individuals diagnosed with any type of insulin-dependent diabetes mellitus ≥ 1 year
• Willing to perform up to 12 finger-pricks during each day of out-patient measurements
• Signed informed consent
• For women of childbearing potential: Willing and able to practice FDA approved birth control during the duration of the investigation
• Subject has a 2.4 GHz wireless internet connection at home (standard in normal routers) to be used in the study

Exclusion Criteria:

• For female subjects: Pregnancy or breastfeeding
• Skin phototype VI categorized by Fitzpatrick scale measured on thenar
• Subjects not able to understand and read local language
• Cognitive impairment, or 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 thenar (measurement site)
• Reduced circulation in right hand evaluated by Allen's test
• 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
• Any disorder, which in the investigator's opinion might jeopardize subject's safety or compliance with the protocol
• 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)
• Subjects currently participating in another study
• Subjects who have participated in the study IDT-1904-RO/RSP-21 or RSP-19.
• Incapacity for consent