This is a single-centre, open label (unblinded) prospective study investigating the performance and safety of FiberSense system in diabetic patients (Typ I and II). In the period of up to 30 days the performance of the FiberSense system is evaluated against laboratory gold standard method during 6 in-clinic sessions.

The FiberSense system is intended to be used by diabetic patients in a home use setting as a CGM system using the interstitial fluid (ISF) glucose as an indicator of blood glucose levels.The purpose of this study is to assess the performance of FiberSense system across the glucose measurement ranges as compared with a laboratory standard reference method in diabetic patients (Type I and II) during in-clinic glucose challenge sessions. At the same time the blood glucose values are recorded by comparator continuous glucose monitoring (CGM) system and self-monitoring blood glucose system (SMBG). The safety aspects are also investigated during the wearing time of up to 30 days.

Inclusion Criteria:

• Male or female age ≥ 18 years old.
• Type I or II diabetes mellitus.
• Women who are not pregnant, lactating or planning a pregnancy during their participation in the clinical study. If of child bearing potential, the patient must agree to abstain from sexual intercourse or use reliable forms of contraception (e.g. condom or diaphragm with spermicide or oral contraceptives) to prevent pregnancy for the length of the clinical study.
• Willingness, ability and commitment to comply with the testing procedure and follow-up outlined in this protocol including (but not limited to) frequency of clinic visits, use of pre-specified glucose monitoring device.
• Willingness to abstain from swimming during their participation in the measurement phase.
• Willingness to abstain from air travelling during their participation in the measurement phase.
• Willingness to avoid strong magnetic and electrical fields as well as proximity to sensitive medical devices due to the possible electromagnetic interference during their participation in the measurement phase.
• In the opinion of the investigator, absence of any physical limitations, addictive diseases, or underlying medical conditions (including mental health) that may preclude the patient from being a good study candidate.
• Written informed consent to participate in the study provided by the patient.

Exclusion Criteria:

• Poorly controlled diabetes mellitus with HbA1C >10%.
• Known microvascular (diabetic) complications (other than diabetic non-proliferative retinopathy), such as e.g. history of laser coagulation, proliferative diabetic retinopathy, known diabetic nephropathy (with glomerular filtration rate (eGFR) < 45 ml/min) or neuropathy requiring treatment.
• History of significant hypoglycemia unawareness, or a history of severe hypoglycemia (requiring emergency medical intervention) within the last 6 months.
• Currently pregnant, as demonstrated by a positive pregnancy test at screening and prior to enrollment.
• Impaired hepatic function measured as aspartate aminotransferase (AST) ≥ three times the upper reference limit.
• Impaired renal function measured as creatinine > 1.2 times above the upper limit of normal.
• Any active acute or chronic disease or condition that, in the opinion of the investigator, might interfere with the performance of this study.
• Any active acute or chronic infectious disease that, in the opinion of the investigator, would pose an excessive risk to study staff.
• Current use or recent exposure to any medication that in the opinion of the investigator could have an influence on the patient's ability to participate in this study or on the performance of the test device.
• Extensive skin changes/diseases that preclude wearing the required number of devices on normal skin at the proposed application sites (e.g., extensive psoriasis, recent burns or severe sunburn, extensive eczema, extensive scarring, extensive tattoos, dermatitis herpetiformis).
• Have a known allergy to medical-grade adhesives, or known hypersensitivity to any of the products used in the study.
• Known current or recent alcohol or drug abuse
• Blood donation of more than 500 ml within the last three months
• Currently participating in another investigational study protocol where the testing or results may interfere with study compliance, diagnostic results, or data collection.
• Has a MRI scan, CT scan, diathermy or flight scheduled during the proposed study participation.
• An identified protected vulnerable patient (including but not limited to those in detention, or a prisoner).