The primary objective of the study is to evaluate the safety and effectiveness of the G4 System (System) when used as an adjuvant to blood glucose testing over a 7-day period in pediatric subjects with diabetes mellitus.

System effectiveness will be primarily evaluated with comparison to laboratory reference Yellow Springs Instrument (YSI) venous sample measurements. The system performance will be evaluated in terms of point and rate accuracy of the system in reference to YSI. The point accuracy is measured as the proportion of G4 System values that are within ±20% of YSI reference value for glucose levels >80 mg/dL and ±20 mg/dL at YSI glucose levels <80 mg/dL. The trend accuracy of the device performance, i.e., continuous glucose error grid analysis, will be evaluated as well as the temporal accuracy at different glucose rates of changes and different glucose ranges (hypoglycemic, euglycemic, and hyperglycemic ranges). The primary matched paired (Sensor-YSI) measurements will be collected during one in-clinic session. System effectiveness will also be evaluated with SMBG measurements similarly.

Safety data of the system will also be collected and safety will be characterized by the incidence of Adverse Device Effects (ADE) experienced by study participants.

Other objectives include the evaluation of device performance at an alternate site (the upper buttocks).

Inclusion Criteria:

• Ages 2 to 17 years ;
• Diagnosis of diabetes mellitus;
• Willing to participate in one 7-day Sensor wear period;
• Willing to wear 2 systems simultaneously;
• Willing to take a minimum of 7 fingersticks per day during home use with a blood glucose meter provided;
• Willing to attend one in-clinic session of up to 6 hours duration. Clinic procedures where blood sampling via SMBG and/or venous YSI method, depending on age;
• Subject or guardian is able to speak, read, and write English.

Exclusion Criteria:

• Extensive skin changes/diseases at sensor wear site that preclude wearing the Sensor on normal skin (e.g. extensive psoriasis, recent burns or severe sunburn, extensive eczema, extensive scarring, extensive tattoos, dermatitis herpetiformis);
• Known allergy to medical-grade adhesives;
• Require a magnetic resonance imaging (MRI) scan, computed tomography (CT) scan, or diathermy during the wear period. If any of these procedures are required urgently during the study, subjects will notify the study staff, end their continuous glucose monitoring (CGM) session, and remove their sensor.

Pediatric subjects with diabetes mellitus