Table 2

Current methodologies for neonatal glucose monitoring

Glucose monitoring modality	Type of analyser	Source of sample	Advantages	Disadvantages
Laboratory analysers	Glucose oxidase	Plasma/serum sample	Most accurate, gold standard	Invasive, requires blood sampling Multiple sampling can cause anaemia Long lag time from blood sampling to obtaining results
Laboratory analysers	Hexokinase	Plasma/serum sample	Most accurate, gold standard
Point-of-care analysers	Traditional enzyme-based (Glucose oxidase)	Whole blood sample	Fast results Minimal blood requirements	Invasive May be inaccurate at low glucose concentrations
Point-of-care analysers	CAST-GBP technology	Cutaneous sample	Non-invasive and pain free Comfort and patient adaptability	Early stage development
Continuous glucose monitors	Traditional enzyme based subcutaneous	Interstitial fluid sample	Detects episodes of hypoglycaemia Real-time rather than intermittent sampling	Invasive Interstitial sampling may be inaccurate or levels not detected in infants with oedema Foreign body response and biofouling-induced sensor degradation
	Microdialysis	Interstitial fluid sample	Sensor is outside the body Minimal subject-to-subject variability	Open wound with significant tissue inflammation Long lag times needed for the interstitial fluid to reach the sensor Discomfort because of presence of protruding microdialysis probes
	Spectroscopic transdermal	Tissue/blood sample	Non-invasive and pain free Comfort and patient adaptability	Large background signal from skin pigmentation, body water content and ‘glucose-like’ substances in the tissues Low specificity to glucose Large subject-to-subject differences Strong effect of temperature on glucose response Requires calibration with blood glucose measurements
	Induced glucose sampling transdermal	Interstitial fluid sample	Minimally invasive	Requires physical or chemical enhancement of glucose diffusion through the skin

CAST, Center for Advanced Sensor Technology; GBP, glucose binding protein.