Participants will perform blood glucose monitoring (BGM) over the course of 14 days and, in parallel, wear continuous glucose monitoring (CGM) systems. Because current CGM systems typically achieve a lower level of analytical accuracy than BGM systems, participants will perform at least 5 blood glucose (BG) measurements per day. In addition, CGM systems are used to obtain minimally-invasive high-frequency glucose measurements to fill the gaps between BG measurements.

Inclusion Criteria:

• At least 18 years of age
• Written informed consent
• Subject is legally competent and has the capacity to understand character, meaning and consequences of the study
• Subject is willing to refrain from intake of salicylic acid and ascorbic acid and medication and/or compounds containing these substances

Exclusion Criteria:

• Anamnestically known diabetes mellitus
• Severe acute or chronic disease with potential risk of being adversely affected by the study procedures (at the study physician's discretion)
• Current constitution that compromises the subject's capability to participate in the study (at the study physician's discretion)
• Pregnancy or lactation period
• Known severe skin reactions to adhesives
• Blood donation within the previous two months (according to the subject's statement)
• Language or other barriers potentially compromising an adequate compliance with study procedures