A Study to Test a New Multi-Analyte Sensor During Meal Tests

All eligible participants will be transferred to the investigational device, the PercuSense Atlas Health Multi-Analyte Sensor (MAS). In addition the participant will also wear the commercially available continuous glucose monitor (CGM), the Abbott Libre 2 Plus. This is a single-site, participant-blinded feasibility study designed to generate preliminary data on continuous interstitial glucose, ketone, lactate, and oxygen measurements using the PercuSense MAS during standardised metabolic challenges. Participants will be recruited from St Vincent’s Hospital Melbourne. Two cohorts will be enrolled: Cohort 1 will include 10 adults with a clinical diagnosis of diabetes treated with insulin, and Cohort 2 will include 10 adults without diabetes. Following written informed consent, participants will be screened for eligibility which involves medical history review, clinical assessment and physical examination. On Day 1, eligible participants will undergo insertion of masked study devices. Two MAS devices will be inserted subcutaneously, one in the outer aspect of the arm on each side to enable continuous monitoring of glucose, ketone, lactate, and oxygen. A commercially available continuous glucose monitoring device (CGM; Abbott Libre 2 Plus) will also be inserted according to participant preference into the abdomen, thigh or in the back postero-laterally just above the beltline. An intravenous cannula will then be placed for serial venous blood sampling. Blood samples will be collected at baseline and at 15-minute intervals throughout the study visit (approximately 6 hours). Participants will begin a standardised meal test. A standardised test meal requires participants to eat a meal containing 65g of carbohydrates. For example, a toasted cheese sandwich and a glass of milk or a fruit juice. Following the meal test, a blood pressure cuff will be applied to the upper arm above the investigational sensor and inflated to 50mmHg above systolic pressure and also perform handgrip exercises to achieve reduced blood flow with the aim of inducing a transient increase in lactate for up to 10 minutes. The arm cuff will then be deflated at the end of the 10 minutes. Subsequently, participants will consume an exogenous ketone drink. The ketone drink (100 mLs) contains a pure ketone substance dissolved in a commercially available low-calorie drink. The first blood collection will commence before the meal test to collect baseline values and then continue every 15 minutes over the duration of the study visit (approximately up to 80mL over 6 hours), with an additional two blood collections (up to 10mL) during the arm blood pressure cuff procedure On Days 2 and 3, participants will remain in the outpatient setting (home) while continuing to wear the MAS and CGM devices. During this period, they will perform capillary glucose and ketone measurements via finger-prick testing. On Day 4, participants will return to the clinical site to repeat the standardised meal test, blood sampling protocol, arm cuff blood flow restriction procedure, and administration of a second ketone drink consistent with Day 1. At End of Study all study devices (MAS and CGM), will be removed and study phone returned at clinical site. Adherence of participants to the intervention will be monitored throughout the study. This will be achieved through study team members reviewing device data by direct observation during the meal tests and uploads into the mobile app platform at other times.